CHAPTER XXI 

 THE MOSQUITOES 



MOSQUITOES (Culicidae) are of the greatest importance medically, 

 not only from their influence upon health in general by reason of inter- 

 ference with sleep and possibly from direct transmission of disease, but, 

 more specifically, they are the only means by which it at present appears 

 possible to bring about infection with such diseases as yellow fever, 

 malaria, filariasis, and possibly dengue. In addition, many diseases 

 of animals are transmitted by mosquitoes. 



The Culicidse differ from all other Diptera in having scales on their 

 wings and generally on head, thorax, or abdomen. 



To identify a mosquito, examine a wing and note the scales; also note the presence 

 of two distinct fork cells and, in addition, that the costal vein passes completely 

 around the border of the wing, making a sort of fringe with its scales. Mosquitoes 

 undergo a complete metamorphosis, there developing from the egg a voracious, 

 rapidly growing larva; next, a nongrowing, nonf ceding stage the pupa or nymph. 

 In this latter the head and thorax are combined is an oval body, from the back 

 of which projects the siphon tubes; and tucked in ventrally is a small tail-like 

 appendage. 



The fully developed insect emerges from the pupa. 



The Culicidae belong to the suborder Nematocera. These have long articulated 

 antennas and include four families: Culicidae, Chironomidae, Simulidae and Psycho- 

 didaj. 



The principal mosquito-like, blood-sucking Diptera which are 

 frequently mistaken for mosquitoes none of which have scales on their 

 wings are the following: 



1. Chironomidae or Midges. The blood-sucking species of Chironomidae, which 

 are found in- most parts of the world, belong chiefly to the genus Ceratopogon. These 

 midges are of very small size, about ^2 m ch long, are able to get through netting 

 and, usually being in swarms, they are exceedingly troublesome. The antennae 

 have thirteen joints and the wings are shorter than the abdomen and have only 

 longitudinal veins. One of the midges, the "jejen" of Cuba, is a great scourge, 

 its small size enabling it to enter eyes and nostrils. The larva of Chironomus is a red 

 worm-like creature; the pupa has a tufted head. 



2. Simulidae or Buffalo Gnats. These are small blood-thirsty insects only about 

 % inch in length. The thorax is humped, the legs are short and the proboscis 



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