The fact that this species is a parasite in its larval state does not seem to be questioned, but that it is a parasite on one or more species of Isosoma is, I understand, doubted by some entomologists. For the past two years the writer has had no doubt that such was the case; but it is possible the evidence upon which such a conclusion is based may not be generally known. For this reason a brief summary of observations may not be out of place.

That it is a parasite on Isosoma hordei seems evident from the following: A single joint of rye containing several galls formed by Isosoma hordei was put into a bottle and corked up so that no insects could get out or in. In due course of time a specimen of E. Allynii was found in the bottle, and the hole from which it had gnawed its way out of one of the galls was plainly to be seen. Afterward the other galls gave forth I. hordei. In this case there could be no question but that the specimen of E. Allynii came from the gall made by I. hordei. If no hordei had hatched from the other galls, this would have been evident, for the galls made by this species are too characteristic to be mistaken by any one at all familiar with their work.