364 ENTOMOLOGICAL SOCIETY 



thing which has been established concerning the habits of a re 

 stricted group, the fullest proofs should be demanded. 



In reply, Prof. Riley stated that the very arguments which Mr. 

 Howard brought out were the ones which had been adduced by 

 English observers and others against the phytophagic habit of 

 Isosoma which has since been so surely proved. The dearth of 

 infested seeds the second year with the Danish fir cones might be 

 the result of dimorphism or alternation of generation in the species, 

 the bisexual generation having a different habit, and this view is 

 supported by the fact that all of the specimens bred by Mr. Borries 

 in 1887 were females. In his opinion the actual feeding of the 

 larvae of the Megastigmus upon the germ of the seed of the Oregon 

 Pine is positive proof of a partial phytophagic habit, and in con 

 nection with many facts in reference to the question of inquilines 

 would suggest that perhaps the true explanation is to be found in 

 the combination of the parasitic and phytophagic habits in many 

 genera of the true parasitic families. It is quite likely, in other 

 words, that in these parasitic Hymenoptera we have a case quite 

 similar to that of some of the partially parasitic bees and beetles, 

 viz., that the young larva, after first partaking of the egg or the 

 larva of its host, feeds on the vegetable food stored up by the host 

 parent. In other words, Megastigmus may first feed on the seed- 

 infesting larva and after destroying it may feed upon the seed 

 itself. 



Prof. Riley then read the following: 



NOTE ON GALERUCA XANTHOMEL^NA. 

 BY C. V. RILEY. 



Prof. John B. Smith at New Brunswick, N. J., and myself 

 here at Washington have taken particular pains the present year 

 to ascertain definitely the number of generations of Galeruca 

 xanthomelcena that occur in our respective localities, and at 

 the late meeting of the Entomological Club of the American Asso 

 ciation for the Advancement of Science our conclusions were pre 

 sented, the observations in either case being so carefully made 

 that there could be no doubt as to their accuracy. The results 

 showed that the species is single-brooded at New Brunswick, and 

 double-brooded here at Washington, with a tendency to a third 

 and even a fourth generation. I have had considerable corre 

 spondence with Mr. Smith on the subject, and present for record 

 the following letter from him, which explains itself, and which 



