Glyceria sweet-grass

Larvae of a number of species of Chironomidae (non-biting midges) live in tunnels in decaying leaf sheaths under water. Their tunnels are open at both ends, and the larvae feed on particles they obtain from a water current they create in the tunnels. They do not feed on tissues of their “host plant”, therefore are no miners, and are not treated here.

Dichotomous table for leafminers

1a larva a maggot; pupation either within or outside the mine => 2

1b larva with feet and chitinised head; pupation outside the mine => 11

1c gallen etc => Tabellen voor alle parasieten per soort

2a larva: mandible with 1 tooth; at the start of the mine (often within a leaf sheath) an egg shell at the outside => 3

2b mandible with at leat 2 teeth; no egg shell visible => 4

3a larvae from Mayi: Hydrellia griseola

3b larvae in April: Hydrellia thoracica

4a larva: cephalic skeleton of Phytomyzinae-type; puparium in the mine => 5

4b cephalic skeleton of Agromyzinae-type; pupation outside the mine => 7 *

5a puparium metallic black; spiracula don’t penetrate the epidermis: Cerodontha pygmaea

5b puparium orange brown; front spiracula penetrate the epidermis => 6

6a puparium ventrally with a broad dark brown length line: Chromatomyia fuscula

6b puparium ventrally uniformy light brown: Chromatomyia nigra

7a larva: front spiracula strongly enlarge, disc-shaped; only on Glyceria maxima: Agromyza alunulata

7b front spiracula normal; possibly also on other Glyceria-species => 8

8a larva: ventrally behind the mandible a field of broad, small spines: Agromyza nigrella

8b no such field present => 9

9a larva: mandible with 3 teeth: Agromyza lucida

9b mandible with 4 teeth => 10

10a larva: rear spiracula touch each other (occurrence on Glyceria dubious): Agromyza albipennis

10b rear spiracula separated by at least their own diameter: Agromyza nigripes

11a mine long and/or broad => 12

11b mine quite small => 17

12a mine broad, yellow-white, mainly in the leaf tip: Elachista pomerana

12b mine long and narrow => 13

13a larva: with one or more length lines => 14

13b no length lines => 15

14a larva: whitish with 4 reddish-brown length lines: Sedina buettneri

14b yellowish with a brown dorsal length line: Nymphula nitidulata

15a mine inflated: Donacaula forficella

15b mine flat => 16

16a frass in a single line: Elachista poae

16b frass, at least in the oldest part of the mine, in two or more parallel lines: Elachista apicipunctella

17a larva with length lines: Orthotelia sparganella

17b no length lines => 18

18a larva: pinacula colourless (the bases of the setae themselves are black): Cnephasia incertana

18b pinacula black: Cnephasia asseclana

* See also the key to grass-inhabiting Agromyza larvae.

mod 18.v.2019