Author: Willem Ellis

(paniculus) Inflorescence, like in some grasses, with a long central axis bearing a number of branched lateral axes.

The, more or less dish-shaped, widened top part of the flower stalk of Asteraceae (Compositae) where the florets are inserted in the flower head.

The first larval stage of scale insects and whiteflies. Later stages are immobile and attached to the plant, therefore this first, mobile, stage is crucial for the dispersal of the species.

literally: opponent; an organism that in some way has a negative influence, e.g. a competitor or predator.

sclerite (hardened chitine plate) at the dorsal side of a thoracic or abdominal segment in an insect.

sclerite (hardened chitine plate) at the ventral side of a thoracic or abdominal segment in an insect.

A specialised form of setae (“hairs”) in some insects. They consist of a cup-shaped base, with on top a short dagger- or tube-shaped seta. In Triozidae larvae the margins of the abdomen, wing pads and head bear a row of sectasetae, each one of which produces a long, glistening thread of wax A number of […]

Less often used equivalent of siphunculus

A sac, made out of wax threads or silk, containing eggs.

(pl oviparae).Aphids generally during the summer pass through a number of consecutive generations of viviparae, females that asexually produce living young. The final generation that is born in autumn is different, consisting of males and females that, after being fertilized, lay eggs that enable the population to hibernate. These egg-laying females are called oviparae.

With more or less strongly reduced wings.

(pl viviparae). Female aphid that, without fertilisation, produces living young. Often viviparae are wingless (“apterae”), but they may winged as well (“alatae”). Usually a species during summer has a number of generations of viviparae. In autumn male and female aphids are born. The fertilised females (the “oviparae”) lay eggs by which the population passes the […]

Summer dormancy; a period when an insect enters a state of immobility and lowered metabolism, analogous to hibernation.

A mass of conidia, extruded as a white thread Eudarluca caricis, a parasite in the telia of a rust fungus

In aphids the lower lip (labium), that ahs been transformed into a hollow tube. Through this tube the stylets can be pushed out. The stylets, strongly modified mandibles and maxillae, pierce into deeper layers of the plant’s tissue and bring up the sap.

In sawflies it sometimes happens that the oviposition scar functions as a gall for the very youngest stage of the larva; once the scar has been eaten out the larva starts living free on the plant. The scar then is addressed sometimes as a protocecidium, “predecessor of a gall”. protocecidium of an unknown sawfly on […]

The body segments of sawfly larvae are subdivided by deep grooves. The number of these subdivisions, “annulets”, is of taxonomic importance. (From Lorenz & Kraus, 1957)

A pair of short appendages at the terminal segment of some sawfly larva.

Slab of chitin

Larvae of insects with an incomplete metamorphosis, in particular Hemiptera (bugs, aphids and relatives) are often addressed as nymphs.

A female aphid in, or coming out of a gall.

The opposite of holocyclic; see there

The life cycle of some insect groups, like aphids and gall wasps consists of an alternation between a sexual generation and an asexual one. Such a complete cycle is called holocyclic. Some, related species however may have an abbreviated cycle: either only a sexual stage, or continuous asexual reproduction; this situation is called anholocyclic.

An animal that lives in the nest, colony, or burrow and another animal species. In connection with this site generally a larva that lives in, and feeds on, a gall that has been caused by the actual galling insect. The severity of the ensuing competition varies strongly. Galls that are co-occupied by one or more […]

(Often just stigma). A cell in the venation of an insect wing, always at the frontal margin and not far from the tip, that mostly is thickened and darkly coloured.

The hair cover of a plant.

The “plume” on top of the fruit of most Asteraceae; Also to total of them within a flower head.

Flower head; the inflorescence of Asteraceae and some other families that is so compact that it looks (and functions) like a single flower.

A stalk supporting an inflorescence

Having a large number of generations per year; in warmer regions having one or more generations also during the winter. There is only a short period of pupal rest.

(pl teleutosori). Currently unusual equivalent of telium.

The large genus of rust fungi, Puccinia, is characterised by having two-celled teliospores. However, a, generally quite small, minority of the spores is unicellular; they are addressed as mesospores.

Needle-shaped.

Spindle-shaped.

Mostly brown plates at the ventral side (rarely also at the dorsal side) in some larvae of the genus Ectoedemia; they only occur in the youngest stages. young larva of Ectoedemia atricollis in its mine.

(pl uredinia). The third stage in the life cycle of rust fungi, after the aecia and before the telia.The mostly look like light brown to chestnut brown powdery, up to 2 mm large pustules.

One generation per year.

The body part of an insect between head an abdomen, that in the larval stage (generally) bears feet, and in the imago (generally) also wings.

Less currently used synonym of teliospores.

Fungus of the class Ustilaginales.

Fungus of the class Pucciniales.

Generally: stalk; applied in particular for the stalk of a teliospore.

(pl telia). The fourth stage in the life cycle of rust fungi, Pucciniales. Generally they appear after the uredinia, and are darker in colour. Puccinia ptarmicae: a telium under the microscope

Mature larvae of gall midges often have ventrally on the thorax a chitinous rod, at the front end ending in a small fork. The spatula is used by the larva when it has to force itself out of the gall. Most of the spatula lies internal, just below the epidermis; only the part above the […]

Living freely on the leaves; phrase used in particular for gall mites.

(pl sori). A compact cluster of spores forming fungal tissue, like an uredinium or telium.

Hairs of plants, and also their modifications in an erineum, are fundamentally different from the hairs of mammals. In the technical literature they therefore often are addressed as trichomes.

(pl setae). The “hairs” of arthropods differ in their structure fundamentally from those of mammals, and therefore are called setae. Thick and heavy setae also are designated as bristles.

Main axis of a composite leaf, or of fern leaf.

Cushon-shaped.

The sexual stage of a fungus (contrasting with anamorph).

(pl spermonia). First stage in the life cycle of the Pucciniales. It are mostly orange-coloured pycnidia the at maturity exude liquid. Puccinia festucae on Lonicera periclymenum Puccinia festucae

(pl sporodochia). Cushion-shaped organ, at the outer surface of which conidia are formed.

(pl siphunculi). A pair of rod-like appendages on the abdomen, an exclusive character of the family Aphididae, aphids. The exude a viscous liquid containing mainly excess sugars – to obtain the necessary amount of amino acids, aphids need to digest much liquid, and ingest much more sugars than needed. Shape, sculpture and even colour of […]

One-celled fungus, that reproduces asexually by sprouting or cell division. Some groups of fungi are permanently in this stage, but many Ustilaginomycotina, and also the species of Taphrina pass their anamorphic stage as yeasts.

(pl perithecia). Globular or flask-shaped organ, provided with an opening (ostium), containing asci.

Thick-walled cell, derived in a fertilised oogonium, embedded in the host plant tissue. Their biological function mostly is of a resting spore, in particular for hibernation. Two still rather young oospores, each one in its oogonium.

(pl septa). Dividing wall, e.g. in a fungal spore or hypha. Often a septum contains a pore that enables some regulated connection between the protoplasma at either side. Hyphae without septa are called aseptate.

Most fungal infection are local. However, in some species the mycelium pervades the entire plant body. This has important biological implications: the fungus may be dispersed by infected seed, and the fungus may hibernate in the below-grond pats of the plant.

A thick-walled fungal spore that develops from a hyphe cell.

A prolongation of the terminal abdominal segment in aphids. Its shape is diagnostic.

-> caespitulus

(pl caespituli). Cluster of hyphae, conidiophores and conidia free on a leaf, often erupting through a stoma. It forms the anamorphic stage of a variety of fungi, grouped conventionally under the term Hyphomycetes. Instead of the technical term often the word “colony” is used.

(pl sclerotia). A hard, dry of fungal tissue that is resistant to unfavourable conditions and may remain in a resting state for an extended period.

(pl sporangia). A hollow organ, in which spores are formed.

A stalk, branched or not, bearing sporangia.

(pl stromata). A compact mass of fungal tissue; generally reproductive organs are formed inside.

Pin-sized puncture made by an agromyzid female with her ovipositor in the surface of leaf. She subsequently drinks from the extruding sap. Males, not having an ovipositor, drink from the punctures that the females have made. A single female can make many tens of punctures in a leaf. When Agromyzidae are a pest it often […]

(pl stemmata). The individual facets of the eye of an insect larva. They are not lying adjacent to another, like in the imaginal eye.

(pl pycnidia). Cavity in the plant tissue, in which asexual fungal spores (conidia) are formed, and ejected through a pore. Contrary to acervuli, pycnidia are situated deep in the plant tissue, and from the outside recognisable only by their opening.

Many aphid species go through an alternation of hostplants. In spring a fertilised female then starts a colony on a, generally woody, primary host plant. After spring, when the nutritional quality of the host plant’s juices is diminishing, migration takes place to a secondary, non-woody, host plant.

Blotch that originates when a gallery is so densely wound that the separating walls wholly or partly disappear (are eaten away). Sometimes the remnants of the walls are visible as secondary feeding lines; more often the frass pattern indicates a secondary blotch.

Blotch, caused by the larva feeding from the centre in all directions.

Cell or small blotch, often separated from the main mine, where pupation takes place. More or less distinct part of the mine, in which the pupa(rium) is waiting.

Arrangement of remnants of green leaf tissue in a pattern of parallel lines of made by the mowing movement of an agromyzid larva that is grazing away the leaf tissue while lying on its side. Trypeta artemisiae: primary feeding lines

Rear part of the cephalic skeleton with 2 “arms” (character of the Agromyzidae subfamily Phytomyzinae). The cephalic skeletons of the two Agromyzidae in comparison: Agromyzinae (left) and Phytomyzinae (right)

Characteristic form of the cephalic skeleton. Acidiia cognata larva: cephalic skeleton

The exit of the tracheal system. To prevent the entrance of unwanted material the openings have a complex structure. Fly larvae have two pairs of spiracula, one pair just behind the ‘head’, another pair near the end of the abdomen. In Agromyzidae the spiracula mostly are stalked. The tracheae are connected with the outside world […]

Several generations per year.

A mass of protoplasma containing a number of nuclei, not separated by cell walls.

The “stalk” of a leaf.

The barrel-shaped “pupa” of a fly ( not of a midge: midges generally have a true pupa). It merits a word for its own because, although it looks like a pupa, it essentially is the last dried larval skin, with the true pupa inside. Only at rare occasions it is possible to see the real […]

The final larval stage of sawflies often differs considerably from the preceding stages: there are differences in the shape of the mandibles, and often the prepupa is entirely white of bone-coloured. At this stage feeding as stopped and the larva is remarkably sluggish. Scolioneura vicina: prepupa

Special type of ascocarp: flask-shaped, opening with a pore.

The wall of a sporangium or other spore-forming organ. The aecia of rust fungi originally are a hollow bladder, the when ripe burst at the tip; the wall, i.e. the peridium, is forming then a characteristic fringe. The term is applied also to the wall of a cleistothecium.

In cases where the egg is deposited within the plant tissue, this is done either by means of an ovipositor, or by biting a hole in the leaf (mostly a thick vein). This causes a wound reaction of the plant, that may remain long after the mine has been vacated. Fenusa dohrni: mines, each one […]

The lower half of the thickness of a leaf, consisting of loosely arranged cells with large air spaces between them. This tissue functions essentially for the exchange of gasses: supply of carbon dioxide and the removal of oxygen. Fagus sylvatica: transverse section through a leaf with palissade parenchyma and spongy parenchyma below.

A layer of columnar cells (generally one to three cells thick) that form the upper layer of a leaf, just below the epidermis. This section of the leaf is particularly adapted to photosynthesis, and contains the highest number of chlorophyll grains. (Not all plants have a palissade parenchyma, like ferns and grasses.) Fagus sylvatica: transverse […]

An interparenchymatous mine, from where repeatedly pieces have been eaten out of the “roof”, i.e. the palissade parenchyma. At first sight this type of more looks like a piece of leaf diseased by some fungus. When held against the light such a mine has a perforated appearance. Phytomyza heracleana: example of a perforate mine.

The deposition of the egg(s).

Thin-walled part of the wall of the tip of an ascus, through wich the spores are released. Podosphaera myrtillina var. myrtillina: ascus with at the upperside in the foto the oculus

In general aspect similar to normal undifferentiated mycelium.

The anterior opening of the cases of Coleophoridae larve sometimes are perpendicular to the length axis of the case, but in many species it forms a more or less oblique angle. This is called the mouth angle.

The dorsal side of of the metathorax, i.e. the third segment of the thorax.

The dorsal side of of the mesothorax, i.e. the middle segment of the thorax.

The first, foremost, segment of the thorax.

The dorsal side of of the prothorax.

The ventral side of of the prothorax.

Seen from the median line.

On the stem. (Most rust fungi occur on the leaves only, but some are also caulicolous.)

At/on the underside of a leaf.

At/on the upperside of a leaf.

There generally are three to five stages in the larval life of an insects, called instars, each one ending with a moult.

The final moult, the one in which an imago emerges from its pupa.

Cup-shaped.

On, of close by, an imaginary length line over the middle of the body.

Insects have two pairs of jaws: the maxillae, situated deeper in the mouth and with a complicated structure, and the mandibles, large, built of one piece, that serve for biting. In maggots the mandibles are lost, but the mandibles ars still there, and sometimes are useful for identifications. Cerodontha incisa

Small lobe, next to the mesal side of the maxillary palp (techically the fused galea and lacinia of the maxillae). Zeugophora spec. from Medvedev & Zajcev (1978a): Maxilla, with to the left the maxillary palp and tot the right the mala; bottom right the tip of the underlip.

Literally “mantle”, two flaps that in some Coleophora species hang on the anal end at either side of the case; in some species, like C. kuehnella the entire case may be covered. Coleophora ibipennella

Many insects place their egg in or on the egg or larva of their prey; the larva that emerges slowly devours the host larva. To call this behaviour parasitic is not justified, because real parasites, like fleas or lice, need to keep their host alive, rather than to kill it. Therefore this type of insects […]

Bound to die, dying. Term used in connection with a part of an organism: “necrotic tissue”.

In order to deposit her eggs inside the tissue of a living plant the female needs relatively much force. Often the terminal segments are adapted to the job, mostly by being heavily chitinised and hardened, like for example in the Agromyzidae, Cecidomyiidae, and Tephritidae. In the sawflies, Tenthredinidae, the ovipositor has taken the shape of […]

Mine in the sponge parenchyma.

At/from the side.

The part of a gallery mine where the larva resides. Obviously this part is free of frass and therefore gives an impression of the size of the larva, even if it has vacate the mine.

Leaf disk.

Living on two or more plant genera belonging to different families. If these families are closely related, one can speak of “narrow polyphagous”, in the opposite case of “broad polyphagous”.

Living on a single plant genus. If this species contains, within the distributional area of the parasite, many species, while the parasite lives on just one or a few of them, one can call the parasite “narrowly monophagous”.

Feeding om a restricted number of plant genera, all of the same plant family.

Chitinous, X- or H-shaped structure in the “head” of Diptera maggots, on which the mandibles and chewing musculature are attached.

Coleophoridae larve in self-made tubes. Som species are capable to enlarge the tubes in pace with their growth, but other species once of twice have to construct a new one. The first tube then often not only in size but also in shape differs appreciably from the later one(s). Coleophora serratella,youth case For comparison, the […]

A rather uncommon type of mine, occurring in the Agromyzidae. The mines are made in the lowest part of the palissade parenchyma and/or the upper part of the sponge parenchyma. Interparenchymatous mines typically are yellow-green in colour.

The “skin” of a larva or imago.

The order Diptera consists of two groups: midges (Nematocera) and true flies (Orthocera). Larvae of he relatively primitive Nematocera have a slender and a chitinised head. Larvae of the true flies have a much more compact build; moreover the head, with almost all of its organs has been almost completely reduced: maggots.

(pl imagines). The adult, sexual and winged, insect.

Essentially an upper- or (more commonly) lower-surface blotch mine, usually made by a Gracillariidae larva. The larva lines the interior of the mine wit silk; the silk gradually shrinks, causing the mine to bulge. Because the mine is not full depth both sides of the leaf behave differently then. The non-eaten leaf tissue because of […]

When two successive larval stages differs much more strongly that normally is the case, and the impression is given of an extra metamorphosis, one speaks of a hypermetamorhosis. A striking example is given by the transition made by Gracillariidae from a sap drinking stage to a tissue feeding one, that moreover is accompanied by major […]

Construction in which an insect hibernates.

Wound like a snail’s shell.

An autumn phenomenon. The presence of an occupied mine in a dying leaf can block the yellowing process. The tissue around the mine keeps its original green colour, even when the leaf already has fallen to the ground.

A (apt of) a mine that is at least 4 times longer than wide; opposite to blotch mine.

Feeding on plants.

Antiquates synonym for Deuteromycetes

(pl fundatrices).Hibernated, female aphids that start a new colony in spring. The fundatrix has hatched from a fertilised egg. Her feeding activity may induce gall formation.

Mine where (almost) all the leaf tissue between upper and lower epidermis has been eaten away.

Finger-shaped unpaired appendage in front of the head in several Agromyzidae larvae. Phytomyza ilicis

Excrements of phytophagous insects.

Full depth blotch, not containing frass, and invariably with one, more or less central, usually circular, hole. Made by a larva (usually a Coleophora that operates from the outside. The larva first bites the hole in the epidermis, then from that point it eats away as much leaf tissue as it can reach without fully […]

Strongly refractive particles in the conidia of some true mildews. They somewhat remind of shards of glass. Podosphaera fugax

(pl exuvia) Cast larval or pupal skin.

Many species pupate outside their mine. Before vacating the mine they use their mandibles to cut a slit in the epidermis; this slit mostly has a very fixed, more or less semicircular shape. Often it is species-specific whether the slit is made in the upper or lower epidermis. Phytomyza minuscula, vacated mine: illumination from behind […]

(pl erinea). Gall in the form of an abnormal hair cover, often with elongated, strongly curled or apically swollen plant hairs. Erinea are caused by gall mites. Aceria pseudoplatani

Membraneous extension of the upper lip (labium), in fact its outwardly protruding inside. The epipharynx may bear a number of specialised flattened setae. Zeugophora sp., from Medvedev & Zajcev (1978a). From the top down: the clypeus, upper lip (labium) and the epipharynx with specialised, flattened, epipharyngeal seta

(pl pinacula). In Lepidoptera larvae: small chitin plates, often coloured brown or black, on which long setae (“hairs”) are inserted.

Mine that (almost) entirely is restricted to the epidermis; always has a silvery appearance.

The outermost layer of cells of the leaf, in fact, the skin of the leaf. The epidermis consists of somewhat flattened cells that do not contain chlorophyll. The outside wall of the epidermis cells is thickened: the cuticle.

Cephalic skeleton, typiical for the Drosophilidae. Scaptomyza flava

Erysiphaceae.

Peronosporaceae.

At the belly-side, seen from below.

At the upper side, seen from above.

Nearest, nearest to the centre.

Furthest from the centre.

A process in the shape of a (short) finger.

Splitting in two identical branches.

In some species of gall mites (Eriophioidea), mainly in species living on woody plants, next to the normal type of females (protogynes) another type occurs, deuterogynes. They are better adapted to unfavourable conditions; often deuterogynes form the hibernation or dispersal stage.

Extension of the last (10th) segment of a Lepidoptera pupa. It generally bears spines or other structures of species-specific shape.

Damage to a leaf, caused by a larva that locally consumed all leaf tissue except either the upper or the lower epidermis, leaving a conspicuous, very transparent “window”. Window feeding can easily be mistaken for a mine; see the little chapter about “pseudo-mines” window feeding on Annual Mercury especially in fresh feeding traces the thickness […]

The most distal part of an insect foot, consisting of a number of tarsi. The last one generally end in one or two tarsal claws and and attachment pad.

An insect foot has the following joints: first a short coxa (“hip”), a generaly kong femur (“thigh”), a gnerally long tibia (“shin”) and finally some short tarsi.

An insect foot has the following joints: first a short coxa (“hip”), a generaly kong femur (“thigh”), a gnerally long tibia (“shin”) and finally some short tarsi.

An insect foot has the following joints: first a short coxa (“hip”), a generaly kong femur (“thigh”), a gnerally long tibia (“shin”) and finally some short tarsi.

Literally “foreign eating”: the occurrence of a parasite on a “wrong” host plant (usually systematically more or less related with the true host plant). In most cases the larva dies prematurely.

(pl conidiodomata). Specialised structure upon or within which conidia are formed.

Simple or branched fungus hyphae on which one or more conidia are formed. Peronospora radii

(pl conidia). Asexually formed, nonmotile, fungal spores. Erysiphe deutziae

(Literally: small column): rod-like central part of an ovary that has been destroyed by some smut fungi The columella is composed of both fungal and host material (McTaggart ao, 2012a). Sphacelotheca hydropiperis

(= Deuteromycota = Fungi Imperfecti).Fungi generally alternate between an asexual stage, called the anamorph, and a quite different sexual stage, the teleomorph. In many cases only one of the two stages is known, or the relation the two has not yet been established. Often the teleomorphs occurs rarely, maybe not at all. Sometimes several anamorphs […]

Deuteromycetes, subgroup Coelomycetes, that form their spores in a pycnidium. It is an artificial grouping, purely based on the form, not on a systematic relationship.

Deuteromycetes, subgroup Coelomycetes, that form their spores in an acervulus. It is an artificial grouping, purely based on the form, not on a systematic relationship.

Deuteromycota that form their spores on conidiophores that are not located on or in a fruiting body. It is an artificial grouping, purely based on the form, not on a systematic relationship.

Deuteromycetes that releases their spores from a fruiting body, either an acervulus (Melanconiales) or a pycnidium (Sphaeropsidales). It is an artificial grouping, purely based on the form, not on a systematic relationship.

Envelope made out of silk (and often other material, in particular frass) protecting a pupa.

(pl cleistothecia). Fruiting body , ascocarp, of the powdery mildew fungi, Erysiphaceae. They are globular, closed, and contain one or a few asci.

Clublike.

Alternative term for Heterokonta.

Alternative term for cleistothecium.

The arrangement of the setae (“hairs”) in insects. The chaetotaxy is genetically strictly defined. The patterns are characteristic for families, genera and often species. Chaetotaxy especially plays a role in the identification of Lepidoptera larvae, in combination with the placement of the pinacula.

In full: “confer”: compare.

The formal term for the cephalic skeleton of Diptera larvae.

Tissue, formed after an injury, consisting of undifferentiated cells.

An unusual type of aecium, lacking a peridium.

Excretion organs, in function comparably with our kidneys. As is indicated by its name, it consists of number of thin tubules in the abdomen.

One of the types of case that is distinguished within the family Coleophoridae.

One of the types of case that is distinguished within the family Coleophoridae. Coleophora potentillae

One of the types of case that is distinguished within the family Coleophoridae.

One of the types of case that is distinguished within the family Coleophoridae.

One of the types of case that is distinguished within the family Coleophoridae.

One of the types of case that is distinguished within the family Coleophoridae.

One of the types of case that is distinguised within the family Coleophoridae.

One of the types of case that is distinguised within the family Coleophoridae.

The neural system of insects consists of the brain, connected to a ring around the oesophagus, which in turn connects to a ventral strand along the whole of the with swellings, called ganglia, in each of the segments. It often is conspicuous in Nepticulidae larvae Stigmella plagicollella

Living on a number, taxonomically unrelated plant families.

Short lateral branch, like in Larix.

Mine that is made in the upper cell layers of the leaf, i.e. the palissade parenchyma.

Transportable, tubular or rarely helicoidal structure, made of plant material, silk, rarely detritus, in which a larve lives and walks around, and from which it may make a fleck mine. Most often made byColeophoridae larvae.

Said of a species distributed over the more northern parts of Europe, at the same time occurring in the higher mountains.

Arrangement of remnants of green leaf tissue in parallel lines, caused either by the formation of a secondary blotch, or, more typically, by the larva shifting its position while feeding (Hering, 1927a; Hendel, 1928a). Nemorimyza posticata

Motile spores, bearing a whiplash flagellum.

Characteristic arrangement of the frass grains, caused by the larva swinging its rear end slowly to and fro while eating, moving and defecating. This behaviour occurs only in some moth species. Stigmella hemargyrella

A mine that is not longer than three times its width; “Platzmine” in the German literature. Opposite to gallery or corridor mine. See also primary and secondary blotch mines.

Life cycle with two generation per year.

Said of hyphae cells containing two nuclei. In Basidiomycota almost all hyphae are binucleate. In Ascomycota binucleate hyphae occur only after fusion of two compatible uninucleate hyphen, as a preamble to sexual reproduction. A binucleate tissue is called a dikaryon. It is a unique common character of Ascomycota and Basidiomycota, that for this reason are […]

After the larva has made a mine in the upper epidermis it makes, within this mine, a new one in the palissade parenchyma. Unique behavious, known only from Phyllonorycter corylifoliella. A somewhat comparable behaviour is seen in the larva of Phytomyza ilicis.

Conidia: with two oil drops.

(pl basidia). The spore-forming organ of the Basidiomycota on top of which, after meiosis, four spores are formed.

(pl asci), Sac-like organ characteristic of the major fungus group of Ascomycota. In the asci, after meiosis, (in principle 8) ascospores are formed. Pseudopeziza trifolii: asci, between them sterile paraphyses

(pl ascomata). => ascocarp

Ascomycota: a cell out of which later an ascus may develop. In Protomyces they are embedded in the galled host tissue. They have a double wall, the outer one conspicuously thickened.

In Ascomycota: Fruiting body of a fungus, in which asci are formed.

(pl appresoria). Nipple- or, sometimes lobed, discoid appendages of the hyphae of the powdery mildews (Erysiphaceae), with which they are attached to the epidermis of the host plant. Erysiphe deutziae

(pl apothecia). In Ascomycota: A ± dish-shaped organ that bears a layer of asci on top.

Near, or in the direction of, the apex of tip.

To the rear end; opposite to anterior

Foremost, in the front; opposite to posterior.

The asexual stage in the life cycle of a fungus. Reproduction in this stage takes place mostly by the the production of asexually formed spores, called conidia.

The rear pair of prolegs (“abdominal feet”) as they occur in the larvae of sawflies and most moth larvae. They tend to be longer than the other prolegs and may be fused.

Strongly chitinised, darker coloured plate on the terminal body segment, like in Tischeria larvae.

At/on both the upperside and the underside of a leaf; especially in parasitic fungi an important character.

(pl apterae). The wingless stage of aphids; opposite to alata.

(pl altae). The winged stage of aphids; opposite to aptera.

The posterior part of the cephalic skeleton with three “arms”, which is characteristic for the subfamily Agromyzinae. Agromyza anthtracina: cephalic skeleton

Cephalic skeleton, typical for for the family Agromyzidae; in particular the anterior arm is simple, quite unlike in the Tephritidae or Drosophilidae. Ophiomyia beckeri larvs: cephalic skeleton

(pl aecia). The second stage in the life history of rust fungi, Pucciniales. Puccinia poarum: underside of a leaf with aecia characteristically, the spores are produced in a chain only under exceptionally quiet circumstances a picture like this can develop

Less often used equivalent for aecium.

Larvae of Lepidoptera and Tenthredinidae (sawflies) not only have three pairs of thoracic feet, like all insects, but also several abdominal segments have a pair of appendage that look like feet, and have the same function. Usually they have a row or circle of crochets at their tip. A less formal term for prolegs is […]

(pl. acervuli) Fruiting body of a parasitic fungus in the form of a small dish, in which asexual spores, conidia, are formed. It generally is formed just below the plant’s epidermis, that is ruptured when the acervulus is ripe to release its spores.

Two generations per year.