84 THE COMMON MOSiJl ' 1T( )KS OF MINNESOTA 



Aedcs canadensis ai^pears early in the spring- in compan\- with 

 Aedcs sylt'cstris, and being- nearly as abundant, makes the spring 

 invasion of mosquitoes very large. By the end of July thev have 

 nearly disappeared. 



Like Acdrs sylrcstris, the winter is jjassed in the egg stage. 

 The eggs hatch very early in the spring, but not regularly. Headlee 

 states that in Xew jersey several generations follow the first, but 

 that the eggs of each ])rood do not all hatch, a successivelv greater 

 number lying over winter to hatch the next spring. For this reason 

 each brood of adults is successively smaller. Howard, Dvar and 

 Knal) state that all of the eggs hatch in the si)ring if they are in a 

 favorable place, giving one single brood each year. The eggs 

 apparentl}- require freezing before being able to hatch. Where 

 there appear what are apparently later broods, they are thought 

 to be caused by heavy rains washing the eggs from dry places, 

 down into pools of water, or raising the level of the pools so as to 

 ct)ver the eggs. A\"hich of these statements as to the life history 

 is correct we are not in a position to say at this time. 



The larva is of medium size; the head is usually dark colored; 

 the breathing tul)e is two and one-half to three and one-half times 

 as long as broad ; the spines on the breathing tube, numbering 16 

 to 24, bear several short teeth on the lower third or half of their 

 length. The scales on the eighth abdominal segment are twenty- 

 tive to fifty in number, arranged in an irregular group, each scale 

 having a hea\}'. sharp spine at the top and several heavy hairs on 

 the sides. 



^^ e ha\e taken this species in our collections only about the 

 Twin Cities, l)ut there seems little doubt that it is found more 

 widely through the state, pro])abh' thrtnighout the entire state. It 

 has been reported through the northern United States and Canada 

 from Xew Jersey, Xew Hamjishire and Ontario to Montana and 

 liritish Columljia. 



( )ur records are : 



Adults. 



Minneai)olis— June 7. 1914; June 26, 1<)16; July 13. 1016. 

 Unixersity Farm — June 23, 1916. 



Larvae. 



University Farm — May 12, 1914, and July 2, \*H4. In a lagoon 

 and in cattle footprints about the margins. 



