June, 1929] MOSQUITOES OF NEW HAMPSHIRE 7 



Only seven or eight of our New Hampshire mosquitoes are commonly 

 found in houses, the others very seldom coming indoors, although some 

 of them may be common in the surrounding fields and gardens, or on 

 porches at night. 



The length of life of female mosquitoes may vaiy from two to six 

 weeks with some species to as much as two months or more with many 

 of our common woods mosquitoes. The males are always short lived. 



The breeding place of mosquitoes is dependent on the place which the 

 female selects to lay her eggs. Each species has a preference for a cer- 

 tain type of locality for egg deposition, and most of the eggs are depos- 

 ited in such preferred locations. If the desired type of pool is absent, 

 or occasionally for some other reason, the females may deposit eggs in 

 unusual situations. 



THE EGG 



The eggs of mosquitoes are small, elongate, more or less cylindrical 

 and tapering to one or both ends. The eggs are white when first laid, 

 but the color soon changes to browTi or black. The shell usually bears 

 raised lines on its surface, which form a reticulate or lattice-like pattern. 



Some mosquitoes lay their eggs singly or in small, loose groups, while 

 others fasten their eggs together in masses. In the latter case the eggs 

 taper toward one end, are deposited in an upright position with the 

 larger end down, and are glued together with a secretion which hardens 

 on contact with the air. The shape of the eggs tends to give the mass 

 a .slight curve or convexity on the bottom. Such egg-masses are called 

 egg-rafts. The place of egg deposition varies with different species of 

 mosquitoes. Eggs may be laid on the surface of water, on the sides of 

 the container above the water, or on sod, mud, dead leaves, etc., in de- 

 pre.ssions or moist areas that are likely to be filled with water. 



The length of the egg stage depends on the temperature, on rainfall, 

 floods or tides, and on the type of life history. In mosquitoes which 

 lay eggs on the surface of water, the egg-stage is often entirely depend- 

 ent on temperature; the higher the temperature the shorter the egg 

 stage. Under ideal conditions the period from the laying of the egg to 

 its hatching may be less than twenty-four hours. When the eggs are 

 laid in dr}' depressions, they will not hatch until rains, floods or tides 

 fill these hollows and cover the eggs with water. The eggs may lie un- 

 hatched for long periods, but after being covered with water they may 

 hatch in less than an hour. If the depression should fail to be filled with 

 water one year, the eggs ma}' possibly lie over and hatch the following 

 year, although it is not known certainly how long they will retain their 

 vitality. Many of our New Hampshire mosquitoes have but a single 

 generation each year, and the eggs of these, irrespective of temperature 

 or water conditions, must be frozen before they will hatch. In these last 

 species, the egg stage may be eleven months or longer. The egg stage 

 of the different species of mosquitoes will, therefore, vaiy from less than 

 a day to over a year, and perhaps longer. 



