180 Forty-first Report on the State Museum. 



leaves on the smaller brancb.es and twigs of hemlocks, both large and 

 small. The operations of the Grelechia caterpillar had consisted in 

 biting off from six to eight leaves of which to construct a broad, flat, 

 irregular case, within which it lived in a rude silken tube, and fed 

 upon the inside of the leaves. 



No larvse were found within the mines, but from the fact that sev- 

 eral leaves were observed to be fastened together and separated from 

 the twig, it is possible that at the approach of winter they may have 

 abandoned their mines to hibernate, as Dr. Packard suggests that 

 O. abietisella may do, within a silken tube inside of the leaf-case. 



Professor Prentiss states that the injury to the hemlocks was first 

 noticed at Ithaca, at about the first of December, since which time it 

 had apparently increased, or at least become more conspicuous. 

 Hundreds of trees in Cascadilla ravine, near the college grounds, 

 were thus affected. 



Cecidomyia balsamicola n. sp.. 

 And Its Gall. 



(Ord. Dipteea: Fam. Cecidomyid^.) 



For the past two years galls occurring in abundance in some locali- 

 ties, within the leaves of the balsam fir, have been in my possession 

 and under observation, in the hope of obtaining the perfect insect 

 from them for description. Late observations have shown that there 

 is no prospect of securing the imago very soon — certainly not before 

 the lapse of another year — as carrying the larva to its final stage 

 promises to be both difficult and uncertain. In the belief that publi- 

 cation of what is known of the insect and its operations will serve to 

 draw attention to it and aid in the early completion of its life-history, 

 it is herewith given a scientific name, some of the more prominent 

 features of the larva are mentioned, and its gall is described. 



The Gall only Known on the Balsam Fir. 

 The galls have been observed by me only on the balsam firs, Abies 

 balsamea, of the Adirondack mountains, but they will probably prove 

 to be of somewhat wide distribution, for in the collection of the 

 Museum of Comparative Zoology at Cambridge, Mass., is a balsam tip 

 bearing the same gall, which Dr. Hagen informs me was obtained at 

 Shelbourne, N. H., in September 1882, by Professor Farlow. I have not 

 been able to find them on balsam firs in the vicinity of Albany, nor 

 on any other species of Abies examined by me other than balsamea. 



