CHAPTER X 



PHYLUM ARTHROPODA, CLASS INSECTA 



(Continued) 



Order 16. Diptera, Flies. This great order includes the 

 insects with two wings (the flies, mosquitoes, gnats, etc.) 

 and a few degenerate species which have no wings. The 

 hind wings are usually represented by a pair of halteres, or 

 poisers, the mouth parts are fitted for sucking or piercing, 

 and the metamorphosis is complete. More than forty 

 thousand species of Diptera have been described and prob- 

 ably 300,000 more are as yet unknown. Howard says: 

 "Not only have the true flies a superiority in point of 

 numbers, but entomologists are concluding that they prob- 

 ably stand at the head of the insect system in point of 

 evolution, that is to say, they are the most specialized 

 of insects. " They are also of great importance as disease 

 carriers. There are two suborders: 



Suborder 1. Diptera genuina; true flies. 



Section 1. Nematocera (Fig. 52); long-horned flies: mosquitoes, 



crane flies, gall-gnats, midges, black-flies. 

 Section 2. Brachycera (Fig. 53); short-horned flies: horse-flies, 



bee-flies, robber-flies, house-flies, bot-flies, flower-flies. 

 Suborder 2. Pupipara; "ticks" and sucking lice. All parasitic. 



Crane flies (Tipulidce) look like big mosquitoes. They 

 are commonly seen in late summer in pastures and woods. 

 The larvae of most species live in the earth but some exist 

 in water, in rotten wood, or even upon the leaves of plants. 



The mosquitoes (Culicidce) are of particular interest to 

 man. They not only cause inconvenience and irritation 

 by their bites, but also carry some of the most important 

 of human diseases. The eggs of most mosquitoes are laid 

 on water (Fig. 52). They hatch into little "wigglers," 



106 



