280 MOSQUITOES OF NORTH AMERICA 



touched the surface of the water ; then she rose, walked a few steps, and dipped 

 again. This she would do repeatedly (14 to 22 times), when she would remain 

 for a slightly longer time with the last abdominal segment touching the water, 

 and would allow a minute white egg to issue forth upon the surface. In this 

 way she laid at the rate of 3 eggs per minute, resting quietly after every sixth or 

 eighth egg for about 30 seconds when she would resume the process.'^ 



There are many observations on the number of eggs deposited by one female. 

 It has already been shown that in this species the eggs are not laid at once but in 

 batches, at intervals, the last determined by the blood meals of the female. The 

 French investigators found that about half the females died without depositing 

 eggs a second time. Out of 100 females 30 laid eggs the second time and 21 laid 

 eggs from three to seven times. This last was the largest number of ovipositions 

 observed by them in a single female, 



Taylor of Havana states that the number of eggs varies from 35 to 114; the 

 first American commission to Vera Cruz gives the number of eggs as from 40 to 

 150, but in neither case are details given. Goeldi thought that the maximum 

 number of eggs from one female ranges between 50 and 100 and on one occasion 

 there were some in excess of the last number. The French commission found 

 the maximum number of eggs from a single female 144. 



Francis, in the report of the Working Party No. 2, records experiments with a 

 number of females at Vera Cruz. In one of his experiments a female laid 51 

 eggs on October 25th, 24 on November 7th, and 26 on November 8th, a total 

 of 101. 



The French investigators found that generally the first batch of eggs is much 

 the largest, between 70 and 95 ; sometimes there are less and very rarely more. 

 The succeeding batches are smaller and do not go above a maximum of thirty. 



Goeldi considered the death of the female after oviposition a certain index 

 that all the eggs had been laid. The French investigators point out that the 

 number of eggs varies considerably and that one can not draw conclusions with 

 such certainty. They found, on the one hand, that females after having de- 

 posited from 70 to 95 eggs remained alive for several months ; on the other hand, 

 they noted that females which had deposited but 30 eggs refused all food and 

 died after a few days or within a few hours. In one case a female which had 

 deposited 82 eggs died three days later, after having been fed ; dissection showed 

 that 30 partly developed eggs were present. 



The French investigators found that there were small females which laid but 

 a small number of eggs. These females came from larvae which had developed 

 under unfavorable conditions. The number of eggs from such females did not 

 exceed 50 or 60 and sometimes it was even less. The season has a certain in- 

 fluence in this connection. Thus it was found at Eio de Janeiro that the pro- 

 portion of females which died after laying the first batch of eggs was con- 

 siderably less during the warm months than in the cool season. 



Peryassii determined that in order to obtain a full complement of eggs it is 

 necessary to feed the female with blood repeatedly, at intervals of at least every 

 two or three days. 



