10 AMERICAN MUSEUM GUIDE LEAFLETS 



the Arctics it must naturally be very short. In temperate climates the 

 first brood generally appears in April or May, while in October and 

 November the fecundated females seek their winter quarters. 



The female mosquito lays its eggs, from fifty to two hundred in num- 

 ber, on the surface of any convenient quiet body of water. Certain mos- 

 quitoes prefer to lay their eggs on brackish water. Thus, the 

 ., „ a . females of Culex cantator and C. soUicitans, both salt-marsh 



mosquitoes, which were found by Professor Smith in inland 

 swarms, were observed returning to the shore with developed ovaries, and 

 this seemed to him "in the nature of a return migration for imposition." 



Though mosquitoes of the various species may differ widely in many 

 minor details such as size, color, form of scales and markings on the 

 body, wings and legs, in all essential respects of structure and life-history 

 they are similar. The following description, however, applies particu- 

 larly to the local Malaria Mosquito [Anopheles mcundipennis Meigen), 

 which is represented by a series of large-scale ( X 75 diameters) models 

 in the Museum. ( )thcr mosquitoes are treated of incidentally, as they 

 differ from the Malaria Mosquito in some important respect. 



The Malaria Mosquito. 



The Egg. 



Mosquito egos are minute bodies, measuring only one half to one 

 millimeter (one fiftieth to one twenty-fifth of an inch i in length. They 

 are generally ovoid in form, hut the particular configuration of their cov- 

 ering, or shell, of chit in varies considerably in different 

 Anopheles ,.,. ... , , , ,. . . , , . , 



E species. 1 lie egg ol Anopheles (rig. 4) is boat-shaped with 



one end somewhat pointed, the other rounded. The lower 



surface, the bottom of the boat, is strongly convex and reticulated, the 



upper surface, the deck, is more Battened. The egg is provided on the 



sides with corrugated air chambers which serve as floats. When re- 



centlv laid the eggs appear almost white in color, but they darken 



rapidly and in a few hours become nearly black. 



In the process of deposition the eggs of the Common 

 Arrangement ... . . ,. ,, ... ... , 



- £ Mosquito unite to form rait-hkc masses, which are known 



as "egg-boats" or "floats" (Fig. 5). The eggs of Ano- 

 pheles, however, are deposited separately, but they may be found 

 arranged in various patterns on the surface of the water, forming 



