DISEASE-BEARING AMERICAN MOSQUITOES 



35 



winter, this mosquito generally passes the winter in the egg 

 stage. The eggs, which are shaped something like a cigar and 

 measure about half a millimeter in length, are laid on the surface 

 of the water or just above the water-line. They can withstand 

 freezing and may be kept dry for 6 months without losing their 

 vitality. They do not form rafts, as do the Culex, but lie singly 

 or in isolated groups. 



Fig. 35. — Aedes calopus, female. 



Fig. 36. — Aedes calopus, male. 



In about 36 to 48 hours, if the weather is warm, the egg 

 develops into the larva, which also is very resistant, it being 

 apparently able to stand freezing for a brief period. A distin- 

 guishing feature of this larva is the fact that it has a black, 

 barrel-shaped breathing siphon. This larva is easily scared and 

 stays at the bottom of the water a good share of the time. 



If the weather is warm, the larva turns into a pupa in 5 to 

 8 days. The pupa stays near the surface of the water most of the 

 time. In 36 to 48 hours the adult mosquito emerges. 



Aedes calopus is of a grayish color and average to smallish 

 size. It has glistening whitish lyre-shaped marks on the back 

 of the thorax, with silver-white dots on the sides. There are 

 white lines at each tarsal joint and on the palpi, while the 

 scutellum also is white. Outside of the markings, the female is 



