﻿CHAPTER VII 



DIPTEKA OR FLIES; APHANIPTERA OR FLEAS; THYSANOPTEKA 



OU THRIPS 



Order VII. Diptera 



Wings two, membranous, usually transparent and never very large; 

 behind the /rings a pair of small erect capitate bodies — ■ 

 halteres — frequently concealed under membranous hoods. 



No distinct prothorax, all the divisions of the thorax being 



united to form a large mass. Mouth-parts very variable, 



formed for suction not for biting, frequently assuming lite 



form if a proboscis that can be retracted and concealed in a 



cleft of the under side of the lie, id. The metamorphosis is 



very great, the larvae hearing no resemblance whatever to the 



perfect Insects, but being usually footles* grubs or maggots ■ 



frequently the head is indistinct, small, and retracted. 



Pupa variable, either exposed and rather hard, with the 



appendages of the body more or less adherent ; or enclosed 



in a scaly capsule looking like a seed, and when extracted, 



soft and delicate, with the appendages not fastened to the 



body incapable of movement. 



This definition of the Diptera, or two-winged flies, is framed 

 without reference to the fleas, which are wingless, or to a few 

 other parasitic wingless Diptera, such as the sheep-tick. Although 

 the Order is of enormous extent, these exceptional cases air 

 remarkably few. About 40,000 species of Diptera have been 

 discovered, but these are only a tithe of what are still unknown 

 to science. The Order is not a favourite one with entomologists, 

 and by the rest of the world it may be said to be detested. 

 Flies do not display the sort of intelligence we appreciate, 



