90 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



as hosts of boll-weevil parasites and then is complicated by 

 the attacks of other insests on these hosts. The presence of 

 certain weeds near cotton fields indicates the presence of 

 typical weevils, with the probability of the usually associated 

 parasites. The abundance of one species of insect frequently 

 involves the reduction of another by direct or indirect means. 

 It is imperative for economic workers to know their local 

 fauna, because the species under investigation are certain 

 to be affected by many other local species. 



Mr. Schwarz commented on the importance of publishing, 

 or at any rate of collecting, local lists of insects. Among the 

 multitude of local lists that have been published in North 

 America, many of them are of little interest for the reason 

 that they include only species of wide geographical range. 

 Referring to Mr. Rohwer's plan of working out a faunal list 

 of the District of Columbia insects, Mr. Schwarz said that 

 he was greatly in favor of it, and that if the Society should 

 not take any action he would heartily join the individual 

 efforts of those members who take interest in the subject. 

 Practically all active members of the Society are in the employ 

 of the Government and are living within the city; they are 

 laboring therefore under the difficulty that they can do field 

 work only on Sundays or holidays. Mr. Schwarz alluded to 

 the work done by the "Washington Biologists Field Club," 

 which at its home on Plummers Island, in the Potomac River 

 (about 10 miles fr.om Washington), has done considerable 

 work toward preparing a local list of insects of the District 

 of Columbia. 



-Under the heading "Notes and Exhibition of Specimens," 

 Mr. R. A. Cushman spoke on a peculiar habit of the larvae of 

 two parasitic Hynenoptera. He said : 



On May 5, 1911, I found two hibernating larvae of the 

 codling moth (Carpocapsa pomonelld) under the bark of an 

 apple tree. In removing them from the bark both cocoons 

 were broken and the larvie were placed in a glass vial. When 

 'observed two days later both had spun cocoons against the 

 glass, but without dimming the glass. This made it possible 

 to observe the larvae clearly. One of the larva \vas much 

 smaller than the other and of a pasty white coKSV, lacking 



