Hymenoptera

The adult insects have biting mouthparts and two pairs of membranous wings of unequal size; the females have an ovipositor.

De Hymenoptera are divided in two main groups: Symphyta, where abdomen and thorax are broadly united, and the Apicrita, where the two are connected by a narrow and flexible petiole. (in fact, thorax and abdomen are broadly fused in tha Apocrita as well: the petiole is situated between first and second abdomen segment).