98 MOSQUITOES OF NORTH AMEEIOA 



as could be expected and fed continuously, but they showed no disposition to 

 change their condition. 



" As the fragments settled the water became clear and the larvae congregated 

 over the sediment, feeding head down and frequently rooting into it. It was 

 rare that an individual was observed at the surface with the spiracle in breath- 

 ing position. I watched patiently for fifteen minutes at a time, without noting 

 a single individual rising to the top and Mr. Dickerson watched almost con- 

 tinuously one day for two hours and declares that during that time only a small 

 percentage of the entire number rose to the surface. 



" Occasionally a number of specimens would be at the surface, feeding, head 

 up, so that the mouth brushes skimmed the surface, and these were watched 

 on occasions for twenty minutes, vrithout noting any attempt to assume the 

 brfeatfaimg position. In fact, during the two months that these larvae were 

 under daily observation, the rising to the surface to breathe was the rare excep- 

 tion rather than the rule. Usually they were feeding, head down, over the 

 bottom sediment, or head up alomg the sides of the jar and at the top. The 

 mouth brushes serve also- as organs of locomotion and the larvae were able to 

 make their way from one point to another, without moving any other part of 

 the body. They often allowed themselves to sink slowly to the bottom without 

 any motion whatever, and sometimes to sink more rapidly curled themselves 

 up into a ring. Occasionally a specimen got hold of a bubble of gas formed 

 at the bottom and allowed itself to be floated to the surface. It was interesting 

 to watch the little fellows; but as week after week passed it became just a 

 little tedious; therefore, to hasten matters, I placed, March 1st, the two jars 

 first received on a water bath, which kept the temperature as nearly uniform 

 as the varying pressure of the gas allowed — say between eighty degrees and 

 ninety degrees Pahr. 



" A difference in growth was observable after a few days and on March 18th 

 the first pupa was noticed, from which an adult was produced on the 21st, a 

 period of three days. Three other pupae were obtained within a week and these 

 changed to adults in about the same time. 



" March 24th, I made an experiment which resulted fatally. It occurred to 

 me that the slow growth might be due to lack of food and as Mr. Brakeley wrote 

 that his larvae attacked and devoured a small gnat I determined to add food to 

 the water. Accordingly I placed a small lujnp of beef in each of five experi- 

 ment jars. Next day at a casual glance I noted nothing unusual, but March 

 26th, at 8 a. m., I found the insects at the top, tube out and evidently in distress. 

 I fished out all the meat particles at once, but the mischief had been done, and 

 most of the larvae died. Evidently this species does not thrive in foul water; 

 a fact which Mr. Brakeley determined also from his field collections. 



"As the season progressed Mr. Brakeley kept sending in larvae and these 

 matured in such numbers that I was able to supply material in sufficient 

 quantity to enable Mr. CoquiUett to determine that instead of Culex pipiens we 

 had a new species to deal with ; one which will have to descend to posterity as 

 a member of the Smith family, unless perchance it proves to have been previ- 

 ously described. 



"Mr. Brakeley kept a duplicate series of specimens under observation at 

 Lahaway, and his first pupa, from larvae thawed out of ice February 17th, was 

 obtained April 16th, and became adult on the 26th. This gives a period of fifty- 

 eight days in active larval life, at an ordinary indoor temperature, or sixty- 

 eight days if the pupal period is counted. Other pupae and adults developed 

 and the pupal period ranged between ten and twelve days. A small lot of 

 specimens gathered April yth began pupating May 1st, and these had an average 

 pupatTrertSfl of TSight days,,'* 



