partly because it has, he says, seven-jointed antennæ. I am unable to agree with him: at least, after examination of many specimens I can only detect six, though certainly one of them sometimes appears double. In Eriococcus hoheriæ, mihi, there is no room for doubt. But this character of the antennæ is, as Mr. Comstock admits, most uncertain. It will be seen below that the two insects which I propose to place under Rhizococcus have less than seven joints in the antennæ.