Comprises the midges, gnats, crane-flies, gad-flies, &c.
2. Cyclorrhapha: Larva vermiform (no head-capsule). Puparium opening by an anterior “lid.”
Comprises the hover-flies, flesh-flies, bot-flies, &c.
Order: Siphonaptera.
Mandibles fused into a piercer; first maxillae developed as piercers; palps of both pairs of maxillae present; hypopharynx wanting. Prothorax large. Wings absent or vestigial. Larva eruciform, limbless.
Includes the fleas.
Order: Hymenoptera.
Biting mandibles; second maxillae incompletely or completely fused; often forming a suctorial proboscis. Prothorax small, and united to mesothorax. First abdominal segment united to metathorax. Wings membranous, fore-wings larger than hind-wings. Ovipositor always well developed, and often modified into a sting. Numerous (20-150) Malpighian tubes (in rare cases, 6-12 only). Larva eruciform, with seven or eight pairs of abdominal prolegs, or entirely legless. Pupa free.
Includes two sub-orders:—
1. Symphyta: Abdomen not basally constricted. Larvae caterpillars with thoracic legs and abdominal prolegs.