DIPTERA. 



575 



are set in vibration beneath two external valves by the expiration 

 of air. 



Sub-order 1. Pupipara* (fig. 476). Lice flies. The body is 

 stout ; the three thoracic segments are fused together, the abdomen 

 is broad and often flattened. The antennae are short, and often 

 consist of but two joints. The suctorial proboscis is formed by the 

 upper lip (labruin) and the maxillae. The legs are provided with 

 toothed clasping claws, and the wings may be rudimentary or 

 absent. The development of the embryo and of the larva takes 

 place in the uterus-like vagina. The maggot which issues from the 

 egg (without pharyngeal framework or buccal hooks) swallows the 

 secretion of large glandular appendages of the uterus (fig. 451) ; it 

 undergoes several moults, and is completely developed when it is 

 born, which occurs just before it enters the pupal stage. They are 

 parasitic, like lice, on the skin 

 of warm-blooded animals, rarely 

 of insects. 



Braula cosea, Nitzsch., Bee louse. 

 Nyctcrilia Latrcillci Curt., without 

 eyes and is parasitic on species of 

 Vespertilio. MglopkaffUt ovinvs L., 

 Sheeptick. Anapcra pallida Meig.. 

 parasitic on Swallows. IRppobosca 

 equina, L., horse-louse. 



Sub-order 2. Brachycera 

 (Flies). Body of very various 



shape, frequently thick and FIG. ^i7.Gastrophllus equl (after F. Urautr). 

 StOUt, With an abdomen COm- a, Larva. i.Male. 



posed of from five to eight segments. Antennae short, and usually 

 composed of three joints with large, usually secondarily ringed 

 terminal joint, to which is attached a simple or ringed bristle. 

 Wings are almost always present. The larvae live in decaying 

 matter in earth and water, partly also as parasites; they are, in 

 great part, maggots with hooked jaws, and pass into the pupal 

 stage within the moulted cask-shaped larval skin (fig. 477). Many 

 of them have the form of a pupa obtecta. 



Tribe 1. Muscaria. With frontal vesicle; proboscis usually with 

 fleshy terminal lobe ; maxillae as a rule aborted ; larvae without jaw 



* L. Dufour. " Etudes anatomiques et physiologiques sur les Insectes Dipteres 

 de la famille des Pupipares." Ann. de* Sc. A r at., II. ser., Tom. III., 1843.' 



R. Lenckart, ' Die Fortpflanzung und Entwickelung der Pupiparen." A bhand. 

 der naturf. GeselUckaft zu Halle, Tom. IV. 



