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AMERICAN MUSEUM GUIDE LEAFLETS 



The slender and almost transparent neck connects the head with the 

 second division of the body, — the thorax. This is irreatlv enlarged to 

 accommodate the strong wing-muscles which it contains (Fig. 26). 

 The middle segment, which hears the wings, exceeds the other in size 

 and forms the entire dorsal portion of the thorax. 



The delicate membranous wings are strengthened by ribs, or veins. 

 closely beset with scales. The arrangement of scales varies in the dif- 

 ferent species of mosquitoes. The local Malaria Mosquito is distin- 

 guished by the presence of four dark spots in certain characteristic 

 positions on its wings, and hence its specific name "maculi- 

 pennis," or "spotted-winged" (Fig. 23). These spots are pro- 

 duced by the grouping of the scales of the wing veins into dense tufts at 

 these points. The margin of the wing hears several rows of scales, long 



FIG. 23. WING OF ANOPHELES MACULIPENNIS MEIGEN. 



Magnification about 20 diameters. 



and slender scales alternating regularly with rows of shorter ones, pro- 

 ducing a beautiful fringe. 



A pair of small club-shaped organs, the "halteres," or balancers, on 

 the third segment of the thorax, enables the insect to maintain its equi- 

 librium, for without them it performs aimless evolutions in the air some- 

 what after the fashion of a tumbler-pigeon, and it cannot direct its flight. 

 Similar organs are found in all Diptera and they represent a degenerated 

 second pair of wings. 



Each of the segments of the thorax hears a pair of legs. Structurally 

 these are simply hollow, jointed tubes of chitin containing the 

 muscles by which they are Hexed. Externally they are covered 

 with scales, and in certain places they hear line hairs. The legs are 



Legs 





