Disholcaspis sileri (Bassett) [See ID Notes]

The gall of this species, described from an unknown oak in southern Utah, is a monothalamous stem swelling resembling the eastern club gall on white oak. Galls which agree with the Bassett types have been collected by the writer on Quercus gambelii, grisea, undulata, and reticulata at the following localities: Wetmore, West Cliff, Trinidad, and Morley, Colo.; Wagon Mound, Rowe, Tijeras, Socorro, Magdalena, Nogal Canyon, and Fierro, N. Mex.; Prescott, Flagstaff, Williams, Grand Canyon, and in Santa Catalina, Chiricahua, and Huachuca Mountains, Ariz. In all cases the collecting has been done at such a time that the maker has not been reared. The flies probably emerge just as the new wood begins to harden in midsummer.

Quercus reticulata [rugosa], gambelii, subturbinella [turbinella]
Stem galls
Stem swellings
Terminal club, one-celled, Fig 50. Determination in literature as Disholcaspis sileri (Bass.) is probably erroneous.

Holcaspis sileri, new species [see ID Notes]

Galls ovate from a broad base, sessile on the twigs of an oak growing in southern Utah, sometimes elongated at the point but not beaked, shining brown, yet not quite smooth. Many specimens are deeply and irregularly cracked, and from some the epidermis has flaked off. They rarely exceed one-fourth of an inch in diameter, and many are a little less than that. Internally they are harder than H. duricoria, H. globulus and H. rugosus, which they resemble, except that they are smaller. The larval cell is closely imbeded, but separable from the gall. I have reared no gall-flies from these, but have found, on cutting some of them open, several apparently mature female specimens.