OF WASHINGTON. 87 



In the discussion Mr. Gill said that the Chicago contention 

 arose in a discussion on the transmissibility of acquired charac 

 ters. He had mentioned the fact that he had, on a summer's 

 evening, picked up one of a large number of these water-bugs on 

 the Washington streets, and had found it to be Belostoma. A 

 few nights later he picked up another and found it to be Benacus. 

 He then examined some fifty or more and found them all Bena 

 cus. He wished to know whether the two species occur simul 

 taneously or whether they follow each other in point of time of 

 flight. He further said, in regard to Prof. Riley's reference to 

 Belostoma as americanum and to the family as Belostomatidae, 

 that, in his opinion, such names should be considered as feminine 

 nouns and not neuters ; that in the Latinization of the Greek 

 noun it should take on the customary gender of its Latin termi 

 nation. Prof. Riley said that on the whole he agreed with Prof. 

 Gill on this point, but that he had simply followed the custom 

 of the purists. Mr. Schwarz, however, dissented, and thought 

 that the Greek gender should be preserved. Mr. Schwarz also 

 called attention to the peculiar noise which these insects make in 

 flight, which resembles that of an electric battery. He also said 

 that in their marvellous power of flight they are unique in the 

 whole order Hemiptera. The hind wings are very weak, and 

 the fore wings are therefore strongly functional in flight and pos 

 sibly cause the noise by rubbing against some other part. 



Mr. Ashmead stated that he had taken Benaczts griseus and 

 Belostoma annulipes together in numbers in Florida. He 

 thinks that Belostoma americanum, as a rule, however, flies 

 earlier in the season than Benacus. Mr. Heidemann stated that 

 he had found both species on the same night in Washington, but 

 that Benacus was the more abundant of the two. Mr. Howard 

 said that he had seen both species taken on the same night, and 

 that one or both fly abundantly in New Orleans in the month of 

 December. Mr. Schwarz stated that Dr. Hessel of the Fish 

 Commission had told him that since the introduction of the elec 

 tric light in the streets of Washington these bugs have become 

 much more numerous in the fish ponds near the monument, 

 showing that the lights of the city have probably attracted them 

 from a wide area and concentrated them in the nearest water 



