REPORT ON MOSQUITOES. 43 



what, by the opportunity for oviposition and that, when eggs 

 are laid the insect's mission in Hfe is over and it dies. In a 

 general way I believe this to be correct ; but we have learnt now, 

 that mosquitoes may bite even after all the eggs have been laid 

 and it is by no means certain that all species will seize the first 

 opportunity to lay eggs. We have kept specimens in captivity 

 for two months, feeding them on fruit juices and even on blood; 

 but we have believed that these were abnormal conditions which 

 would not hold in the open air. I had determined by observations 

 in 1903 that for the migrants at least, there was no shorter life 

 than from four to six weeks and that, as they had no eggs to 

 deposit, there was no particular period when their life work 

 might be said to be accomplished. 



It is difficult under ordinary conditions to measure the life 

 period from out-door observations, for one brood usually comes 

 before the last of the other is gone, and in the overlapping there 

 is no means of knowing whether there are old or new specimens 

 under observation. The mosquito ^age experiments on the New- 

 ark marshes in 1903 were meant to shed some light upon this 

 subject, and so they did; but they gave only the data for life 

 length on the marshes and not for the forms that fly inland. 



Mr. Brakeley's notes on Culex aurifer^ when carefully collated, 

 proved for that species an adult life of three months at least, 

 from the beginning of May when the last larvae were observed, 

 to the end of July when the adults yet occurred in bloodthirsty 

 swarms. Now aurifer is no migrant and, so far as we know 

 there is absolutely no reason why it should not oviposit where 

 the future brood is to be developed. 



The summer of 1904 was remarkably favorable for practical 

 observations on this point. On all the marshes a heavy brood 

 developed in April and traveled inland during the early days of 

 May. On the Newark marsh the ditching work completely an- 

 nihilated the second brood due about July 4th ; but on the Eliza- 

 beth and Raritan marshes that brood developed. On the Eliza- 

 beth marsh the brood was cut short by drought but sent a 

 delegation of the survivors into the city. But there was no 

 migration to Newark and none to the Oranges or points north, 

 that are usually supplied from Newark. The brood on the 

 Raritan marshes was completely absorbed before it reached New 

 Brunswick. It was small at best and consisted largely of sollici- 

 tans, not one of which reached my city. Cantator covered New- 

 ark during the first week in May and reached Montclair and 

 South Orange about the same time ; but though I am certain that 

 no new migrants reached these points, practically all the speci- 

 mens I received from general collections were cantfitor up to 



