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CHAPTER VI. 



The Anatomy of the Adult Mosquito. 



In its anatomy, the Mosquito conforms to the usual 

 insect type, the body being divided into the three sharply 

 separated regions of the head, thorax and abdomen ; the 

 first accommodating mainly the organs of sense, the second 

 those of locomotion, and the third the digestive and 

 reproductive organs. 



The entire body is covered with a chitinous integu- 

 ment, which is thick and rigid on the dorsum, and over the 

 entire head, and thin and elastic where it connects together 

 the various rigid portions. 



This chitinous " exoskeleton," besides covering the 

 exterior of the body, sends inwards plates and trabeculae 

 which form a beautifully intricate framework supporting 

 the bases of the legs and other appendages ; and in addition 

 to this, the entire intracephalic portion of the intestinal 

 canal, and the ducts of the salivary glands are lined with 

 the same material ; while in the form of the tracheae, 

 tubular involutions of this outer covering ramify minutely 

 throughout every tissue, much in the same way as the blood 

 vessels do in vertebrates. 



The whole of the outer armour is covered with appen- 

 dages of various forms, the most characteristic of which 

 take the form of scales. 



These scales consist of flat plates springing from a 

 narrow pedicle, and differ a good deal in outline, not only in 

 different species, but on different regions of the same insect ; 

 though in any given species and situation their form is very 

 constant, and affords valuable characters in classification. 

 Each scale consists of an anterior and posterior membrane 



