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destructive species — probably some dipteroii, because the seveu specimens 

 of tlie Isosoma bred had emerged from one small hole in a shoot (exhibited). 

 Mr. Percival also noticed a difference in the larvae, remarking "that those 

 ill the roots are of a yellow colour, and those in the growth whitish-looking; 

 they also vary in size." Mr. Fitch had not examined the larvae, being 

 anxious to determine the resulting imagos; he attributed his failure in 

 breeding the Isosoma host to the fact that he had great difficulty in keeping 

 the shoots fresh, as Mr. Percival, being an orchid-grower, had of course cut 

 off the affected parts directly they were noticed. 



Mr. M'Lachlan expressed his belief in the parasitic habits of the 

 EurytomidcB. He also called attention to the volume recently issued by the 

 Bay Society, now on the table, " British Oribatidae, by Albert D. Michael," 

 noticing its chief points of excellence, and remarking that such a work did 

 honour both to the Society and to the author. Mr. Pascoe (who said Mr. 

 Michael always drew his figures from two specimens, one living, and one 

 dead and mounted), Mr. Waterhouse (who said Mr. Michael had presented 

 a beautiful series of his types to the Trustees of the British Museum), and 

 Mr. Dunning (who could not believe that the volume only represented five 

 years' work), all bore testimony to the great value of the work, and to the 

 remarkable figures of the internal anatomy of such minute mites. 



Mr. A. G. Butler communicated the following note: — 



Note on the North Awerican Genus Hemileuca. By A. R. Grote. 



"The genus Hemileuca, established by Walker in the British Museum 

 Lists, has for its type the Bombycid moth Maia of Drury, a black and 

 white Spinner with curious dark red tuftings of hair at the end of the 

 body, most noticeable in the male. The moth is distributed over the 

 eastern portion of North America, and is in certain localities, such as 

 New Jersey, and again in Illinois and Missouri, tolerably abundant ; 

 being easily roused to flight in the daytime. The normal colour of the 

 wings or the ground colour may be considered to be black, with a white 

 median band more or less irregular, and enclosing the discal marks drawn 

 across both pairs. The specimens vary in the density of wing-vestiture, 

 some being very crape-like in appearance and thinly scaled. A number 

 of subspecies have been erected, some of which, like Nevadensis, may still 

 intergrade with the typical form ; otheis, like Yava-pai and Grotei, seem 

 more stable in their characters. But the probabihty is that they are all 

 more or less nearly related to the typical form, the insect being in reality 

 plastic and readily accommodating itself to variation. An examination of 

 a number of the subspecies has shown me that the antennae retain the 

 colour of those of Maia. and thus give a hint of the parentage of these 

 apparently differing forms. And this is true of tlie curious form called 

 Euleucophans tricolor by Dr. Packard, who makes it the type of a different 



