390 Dr. A. S. Packard, Jr's Revision of the 



Mass., (Coll. Harris, Norton). 111., (Norton, Coll. Ent. Soc. Phil.). 

 Virginia and N. Jersey, (Coll. Ent. Soc. Phil.). 



In another specimen from Illinois, which is larger than usual, the 

 rugae on the enclosure are very uniform in size, and converge towards 

 the apex of the enclosure. 



It is difficult to convey in words the slight difference existing be- 

 tween the species of this group, which agree so closely in coloration, 

 size and mode of sculpturing. At present I am hardly inclined to con- 

 sider the last mentioned specimen from Illinois anything more than 

 a variety, though the mode of sculpturing of the thoraco-abdominal 

 ring, or propodeum, usually presents easy and most reliable characters 

 for the discrimination of the species. This species will be recognized 

 by the smooth and polished vertex of the head, which in front becomes 

 rougher, puncto-striated and quite hairy. The silvery pile on the 

 clypeus extends up on the orbits, and suddenly terminates about mid- 

 way between the ocelli and insertion of the antennas, and it also differs 

 in the sculpturing of the propodeum. When other species shall have 

 been added, this description will have to be amended. Indeed, for the 

 study of this group, we have as yet the most scanty material, and 

 many conclusions as to the limits of the species, and genera even, 

 will, with time and acquaintance with new forms, ultimately undergo 

 important modifications, and we would here call the attention of ob- 

 servers and collectors to the importance of filling up the gaps in our 

 collections of the members of this most interesting, as it is difficult, 

 group of hymenoptera. 



This species breeds in the stem of the Elder, where it tunnels 

 rather irregular holes, in company with Stigmus fraternus. My 

 specimens appeared in the middle of May. The specimens of El- 

 der containing these insects were communicated by Mr. James An- 

 gus, who has done much towards clearing up the history of our 

 fossorial hymenoptera. A full description, with figures, will be given 

 in a paper on the early forms of the higher hymenoptera, now nearly 

 ready for the press. 



PEMPHREDON, Latr. 

 Pemphrcdon, Latr, Hist. Nat. Ins. xiii, 1805. 



9 • Head unusually large, cuboidal, the sides being parallel. Ocelli 

 placed near together in an equilateral triangle on the vertex; eyes long 

 and narrow ; front with straight parallel sides, somewhat hirsute ; an- 

 tennas rather long aud slender, the joints somewhat convex, elongated, 

 sutures distinct; scape with 2d joint as long as the 3d and 4th together. 



