OF WASHINGTON. 15 
America and Europe. The species were just such as would be 
expected from a country characterized by low herbage, with the 
exception of Urocerus Jiavicornis* which had doubtless been 
introduced in timber. 
Dr. Riley made some remarks on the phytophagic habits of the 
genus Isosoma, instancing further corroborative proof thereof as 
shown by the habits of a new species which he described as /. 
grande* and in which he had been able to examine the female in 
the act of ovipositing. 
Dr. Riley gave a description of a new species of Acrobasis 
(A. vaccinii} which, in the larva state, is the w r ell-known 
'Cranberry Fruit-worm," hitherto unknown in the imago state. 
He criticised the conclusions recently assumed in the Bulletin 
of the Brooklyn Entomological Society as to the lignivorous 
habits of Rhyssa lunator, giving his own experience to show that 
it is parasitic. 
Dr. Riley also criticised a recent report in Psyche of Mr. 
Lugger's statement in reference to the habit of Tiphia and 
Rhipiphorus as found upon Lachnosterna fusca, stating that 
the account of the oviposition of both species was manifestly 
incorrect. 
DECEMBER n, 1884. 
Ten members present. President Riley in the chair. 
Mr. H. G. Hubbard was elected a member of the Society. 
Mr. Stewart exhibited a large number of insects collected at 
the electric light, on the dome of the Capitol. Mr. Schwarz 
remarked that among the insects thus collected, there were many 
hitherto not known to be attracted by light. Prof. Riley also 
spoke upon the collection, and Prof. Riley remarked that he was 
called upon the latter part of September by the architect of the 
Capitol, Mr. Edward Clark, for advice as to the disfigurement of 
the buildings, which had been cleaned at great expense during the 
summer. He found that the hosts of small soft-bodied Dipterous 
and Neuropterous insects, attracted by the electric light, had made 
the building a paradise for spiders, which, by their webs and the 
carcasses of their victims, had sadly disfigured the building. He 
