210 INSECTS 



In cool or cold weather all the stages are lengthened and, 

 whereas eight days from egg to adult is perhaps a normal 

 period, this may be increased to two or even three weeks. 

 The adult male is incapable of sucking blood; but the 

 female is ready to bite twenty-four hours after she be- 

 comes developed, and in three or four days thereafter is 

 ready to lay eggs. The life period of the male is always 

 short, since his only function is to fertilize the female. 

 The life of the female depends upon her ability to find a 

 place for her eggs. When she has placed them her pur- 

 pose in life is filled and she also dies. If she finds no 

 suitable place she may live for weeks and bite several 

 times. Those females that develop late in fall do not 

 feed after they are fertilized, but seek some convenient 

 hiding place in a cellar, barn or outbuilding and remain 

 there dormant throughout the winter. They become 

 active again in May, but larvae are rarely found in any 

 number until well along in June. This species occurs 

 throughout North America and a close ally occurs in the 

 old world. 



The yellow-fever mosquito, Stegomyia calopus, or 

 fasciata as it used to be called, is a smaller species, black 

 in color, with white marking on the body and legs. It is 

 rather a pretty creature, an inhabitant of the more 

 southern states and of the tropical and subtropical 

 regions of America generally. On the Atlantic coast it 

 does not extend normally north of Virginia, and this 

 marks the limit to which yellow-fever may extend under 

 ordinary conditions. I am not unmindful of the fact 

 that yellow-fever has occurred in New York and Phila- 

 delphia; but the conditions permitting these epidemics 

 are now understood and cannot be again reproduced. 



In habit, the Stegomyia is not unlike C. pipiens, and 

 like it breeds in all sorts of dirty water. It is very sensi- 

 tive to cold, and the first frost puts an end to its activi- 



