348 AGRICULTURAL EXPERIMENT STATION. 



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

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

 almost continuously one day for two hours and declares that 

 during that tim.e 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 sur- 

 face, and these were watched on occasions for twenty minutes, 

 without noting any attempt to assume the breathing position. In 

 fact, during- the two months that these larvae were under daily 

 observation, the rising to the surface to breathe was the rare 

 exception rather than the rule. Usually they were feeding, head 

 down, over the bottom sediment, or head up along 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 rap- 

 idly 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 Aveek passed it became just 

 a little tedious; therefore, to hasten matters, I placed, March ist, 

 the two jars first received on a water bath, which kept the tem- 

 perature as nearly uniform as the varying pressure of the gas 

 allowed — say between eighty degrees and ninety degrees P'ahr. 



A difference in growth was observable after a few days and on 

 March i8th 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 lump of beef in each of five experiment 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. Coquillett to deter- 



