99 



hours later the larva? were as lively as ever, there were no dead speci- 

 mens, and adults in some number were in the hood. The conditions 

 were allowed to continue, until it l)ecame certain that development 

 would continue normally, and the experiment was then closed. 



Another series of experiments was made beginning October 4 with 

 "sea salt" as sold in drugstores for the bath. Four jars were used, 

 each with 20 ounces of water, into each of which was placed 50 or 

 more larvee of all sizes and some pupse. To jar No. 1 I added one 

 thirty-second of an ounce of sea salt. October 8 this jar contained a 

 few dead small larva?. October 9 larva? and pupre were both active 

 and developing normall}'. On October 10 there was no change and 

 the experiment was closed. 



To jar No. 2 I added one-sixteenth ounce of sea salt. Four days 

 later, October 8, there were on]}' a few dead larv*, but 15 adults had 

 developed meanwhile. No change taking place, the culture was closed 

 on October 10. 



To jar No. 3 I added one-eighth ounce of sea salt. October 8, four 

 days later, there were few living larvae left, but there were 25 adults 

 in the hood. Next da}^ onl}^ one live larvse remained, and on the 10th 

 all were dead. 



To jar No. -1 I added three-sixteenths ounce of sea salt. Four days 

 later, October 8, 34 adults had issued, and there were j^et a few living 

 larva?. On the 10th all save a few full-grown larviB were dead and 

 the culture was closed. 



The extreme amount of salt used was not large, but the result indi- 

 cates that moderate amounts of salt placed in water would have no 

 injurious effect upon the development of this species. 



NAPHTHALINE. 



Two jars were stocked with large numbers of larva?, from the 3'oung 

 just out of the egg to pup^, in about 20 ounces of water. Into jar No. 

 1 I dropped one large ball of naphthaline and into jar No. 2 I dropped 

 two balls of the same material. 1 watched developments for a week and 

 could not find that the larva? minded it in the least. P^ven the small- 

 est made their way under and around the balls, feeding as freely as 

 they did anywhere else in the jar. 



There was no real expectation that naphthaline could be profitably 

 used to destroy larva?, but it is used not infrequently as a disinfectant, 

 and if it had incidentally any effect in this direction the fact would be 

 worth knowing. 



LIME. 



Eight pails are used in the garden to secure larval material for 

 experimental purposes. They were established June 11 and kept 

 under observation all summer; but })esides pmigeuff only an occasional 



