28 Mosquitoes 



hatch in any time from sixteen hours to at least four- 

 teen months. Temperature, evaporation, agitation, 

 all these affect period of incubation. In the case of 

 raft and Anopheles eggs, emergence was usually in 

 twenty-four hours, sixteen under favourable condi- 

 tions. This rapid development lessens the danger 

 which these forms incur from drying. As to the tem- 

 perature at which development will take place, it 

 varies much with the species. In the case of O. cana- 

 densis, according to Dr. Smith, the larvae will issue 

 early in February, when the water is just above the 

 freezing point. 



Freshly laid eggs are white unless, as shown by 

 Dr. Smith, the deposition has occasionally been re- 

 tarded and the eggs gone on developing and darkened 

 in the ovaries. They will darken, and the shell harden, 

 in an hour or so, after being extruded. So far as 

 the writer has been able to note, ova that dry be- 

 fore they darken will collapse and will not hatch 

 when replaced in water, even if they are the single 

 forms. 



The Blood-Sucking Habit. — Another popular 

 superstition is that a mosquito takes but one meal and 

 then dies, and the author has heard people declare 

 that they knew the insects will sometimes drink until 

 they burst. But after long experience in feeding 

 mosquitoes, we must give them credit for never being 

 quite so greedy or foolish as that. As for their mak- 

 ing only a single repast, it is far from the truth. 

 Most of the species experimented with by Dr. Du- 

 pree would bite at least two or three times, and would 

 lay on an average two or three batches of eggs. This 



