146 E. T. CRESSON. 



are clear; postpetiole smooth and shining with apex punctured. 

 Length 9 .47 inch. 



19. ater, Cress. Proc. Eat. See. Phil, iii, p. 138, $ . 



Hah. — New York. A medium size black species, immaculate ex- 

 cept pale line on anterior orbits and dot before tegulae; antennae 

 with rather broad white annulus and wings faintly smoky; scutellum 

 quite flat and deeply punctured; postpetiole narrow and minutely 

 aciculated ; second and third segments of abdomen densely punctured, 

 the former coarsely aciculated between the gastrocoeli, which are large 

 and deep. Length 9 .57 inch. 



20. apertus, Cress. Trans. Am. Ent. Soe. i, p. 293, 9 . 



Hah. — Can., Ct., N. Y., 111. Closely resembles ater, but rather 

 smaller, with longer antennae and larger head, and easily separated 

 by the punctured postpetiole and less strongly sculptured abdomen. 

 One specimen from Illinois has the apical margin of scutellum pale. 

 Length 9 .50 inch. 



21. acerbus, Cress. Trans. Am. Ent. Soc. i, p. 293, % . 



Hah. — Can., N. H., Mass., 111. A rather small, slender, immacu- 

 late black species with narrow pale annulus on antennae, and hyaline 

 wings. Length % .35 — .50 inch. 



22. chalybeus, n. sp. 



9 — .Black, shining; metathorax and abdomen steel-blue; upper anterior 

 orbits, interrupted on each side of ocelli, annulus on antennae and anterior 

 tibise in front, white; antennse conspicuously flattened towards apex, third 

 joint twice longer than broad and longer than the fourth; scutellum flat and 

 sparsely punctured ; metathorax opaque, strongly punctured, nearly smooth at 

 base, deeply excavated behind, central area small, quadrate, anterior margin 

 indistinct; wings slightly tinged with brown, areolet smaller than usual, nearly 

 triangular; posterior coxse and femora tinged with blue, their coxse nude be- 

 neath and strongly punctured ; abdomen brilliant steel-blue, smooth and pol- 

 ished at apex, segments two to four with small deep punctures becoming con- 

 fluent on disc; first segment broadly dilated at apex and coarsely punctured; 

 basal middle of second segment longitudinally striated, gastrocoeli large and 

 deep. Length .65 inch. 



Hah. — Massachusetts, (Ridings). Closely allied to cseruleus which, 

 however, has a distinct pubescent patch on underside of posterior 

 coxae. 



23. caeruleus, Cress. Proc. Ent. Soc. Phil, iii, p. 149, 9 . 

 Hah.— Can., Mass., Pa., N. J., Md., Va., 111., Ga., Tex. Easily 



known by the beautiful steel-blue color of the abdomen, and some- 

 times of the whole body. The % has the abdomen much more coarsely 

 sculptured and more or less opaque and consequently of a less brilliant 



