156 ENTOMOLOGICAL NEWS. [May, 



which varied from 40" to 78°, averaging a little under 70° for the 24 hours. 

 They fed in much the same manner, kept away from the light as much as 

 possible, passed most of their time at the bottom, but were more lively 

 and more frequently at the surface. The jars were kept covered, except 

 for a few minutes each day, and in none of them did the water foul, de- 

 spite the vegetable and animal matter present in each. 



March 24th I made an experiment that resulted fatally. It occurred to 

 me that possibly the slow growth was due to lack of food, and Mr. 

 Brakeley had written me that the wrigglers attacked and devoured a small 

 gnat which was breeding in his jars, suggesting that possibly a mutton 

 chop might help matters along. 



March 24th I put a small lump of raw beef, chopped fine, into each of the 

 five experiment jars. Next day I could give only a casual glance before 

 going out of town and this showed nothing unusual ; but the day after, 

 March 26th, when I reached the laboratory at 8 a.m., I saw at once that 

 something was wrong, because all the living larvae were at the surface, 

 head down, spiracle reaching the air. In every jar into which I had 

 placed the meat I noted the same appearance, and I hastily fished out 

 every particle. But it was too late : more than half were already dead, 

 others seemed to show a fungoid growth proceeding from the segments 

 so, to prevent their dying, I killed them off with a dose of formalin One 

 large jar received in February was left unharmed, and this was placed on 

 the water bath March 26th. Nothing has come from it at the date of 

 present writing, and nothing may ever come from it ; but its history must 

 be written later. 



But this experiment, fatal as it proved, was of some value. It shows 

 that water too foul with animal decay is not suitable for mosquito larvae. 

 Vegetable decay, and the harder refuse from insect bodies, will help 

 along the development ; but beyond that, the water must be clean. It 

 seems to indicate further that the condition of the water may very largely 

 determine the frequency with which the supply of oxygen must be re- 

 newed from above the surface. In June, with a supply of water at a rela- 

 tively high temperature, in which microscopic life is swarming, I have no 

 doubt Dr. Howard's observations would be exactly duplicated. With 

 the same species in clean water, at a relatively low temperature, the 

 breathing habits are quite different, and the insects obtain, I have no 

 doubt, a goodly poition of their oxygen from the water itself. Just how 

 they do this I am not prepared to say. One thing may be considered as 

 certainly established by this series of observations : the insect can and 

 does hibernate in the larval stage, if this is not, indeed, the prevailing 

 method. Mr. Brakeley scoured the swamps for miles about within the 

 last few weeks, and wherever he found pitcher plants, almost or quite 

 every leaf had its supply of wrigglers. It is not, therefore, a local pheno- 

 mena. Nor is it even suggested that pitcher plants alone furnish breed- 

 ing places where the larvae hibernate ; but they are remarkably safe re- 

 sorts protected to a very marked extent from natural enemies. Is there 



