340 [Mat 



very probably belong to tbe same genus. These species all occur in 

 the group of the white and chestnut oaks. 



3. C. pezomachoides 0. S., G. forticornis Walsh and G. hirta Bassett 

 are apparently wingless females of Teras Hartig (a genus now united 

 with Andricus) ; if such is the case, we may expect the discovery of 

 winged individuals of these species. As these wingless specimens, in- 

 variably females, have always been reared in winter, may they not be 

 dimorphous females of the winged individuals, for which we would 

 have to look out, in such a case, in the early part of summer? Biorhiza 

 Westw. (= Apophyllus Hartig) is distinguished from Teras by an 

 almost obsolete scutellum. The three species named above belong to 

 the group of the white and chestnut oaks. 



4. G. irregularis 0. S., G. majalis Bassett and 0. batatus Fitch 

 are distinguished by the S abdomen being fastened to a rather 

 long, linear peduncle, by the great development of the third antennal 

 joint, which is long, stout and curved; by the smooth mesonotum, with- 

 out any traces of parapsidal grooves ; by the elevated hind margin of 

 the mesonotum ; by the absence of pits at the basis of the scutellum 

 which are replaced by a transverse impression, etc. These species are 

 evidently allied to Spathegaster /rim/or Hartig, of which I possess spe- 

 cimens, the latter having an abdomen of the same structure, no pits at 

 the base of the scutel, the same large wings, with a rather distinct cu- 

 bital vein. etc. But the third antennal joint of S. tricolor, is linear 

 and slender, and not much longer than the fourth; the mesonotum is 

 very finely coriaceous and shows faint impressions, foreshadowing the 

 parapsidal grooves. Trigonaspis Hartig has the third antennal joint 

 elongated and curved, but its abdomen, although pedunculated, has a 

 different structure and the parapsidal grooves are distinctly marked. I 

 conclude, hence, that the three above named N". A. species form a dis- 

 tinct group, allied to Spathegaster. G. verrucarum 0. S., known in 

 the female sex only, shows many points of analogy with these three 

 species, and I should not wonder if the male proved to have a pedun- 

 eled abdomen. 



5. G. spongifica i inanis. coccineae ). coslebs, ilici/olise, singularis, Osten 

 Sae/cenn, and probably the gall-fly of Q. falcata, the gall of which 

 was described by me, Proc. etc. I, p. 69, No. 20, form a distinct group, 

 foreign to Europe, and which will probably have to be separated as 

 a distinct genus. It is worthy of remark, 1st, that the galls of all 

 these species occur exclusively on the group of the black and rea oaks ; 

 2d, that all these galls are built on the same plan; they are monothala- 

 mous, and consist of a globular or fusiform, comparatively thin and 



