NORTH AMERICAN HYMENOPTERA. 159 



distinctly punctured, except the pygidium, which has large, coarse punctures, the 

 first segment short and more transverse than in the other species of the group. 

 Black; mandibles, except apex, clypeus except fore margin, scape, pronotum, 

 tubercles, scutellum and metanotum more or less, femora at tips and on the fore 

 and medial pairs beneath in part, tibiae except a spot within on anterior and hind 

 pair and a spot at apex of latter, tarsi, band on first segment of abdomen, large 

 maculations on the second, third and fourth segments almost touching internally, 

 those on second broadest and truncate within, the others more pointed internally, 

 a band on fifth segment, and ventral segments 2-5 almost entirely, yellow ; head 

 and thorax clothed with rather dense, shaggy, pale fuscous hair ; wings subhy- 

 aline, darker apically, the marginal cell not much broader medially than at apex, 

 and not or scarcely angular beneath, in consequence of which the subiuarginal 

 cell is not narrowed at apex as in the allied species. Length 11 mm. 



California. A very distinct species. 



9. Group singularis. 



The three species constituting this group are easily distinguished 

 by the peculiar striatiou of the dorsulum— anteriorly it runs trans- 

 versely, posteriorly is longitudial. The pygidiuni in 9 is strongly 

 depressed or excavated on apical portion, and is greatly narrowed at 

 that point, and the pygidial segment basally is furnished on each 

 side with long, stiff, hairs. In the % the first joint of flagellum is 

 much slenderer than the remaining joints, the point of junction with 

 the second joint being consequently well defined, the latter joint is 

 also somewhat irregular ; fore femora beneath armed with a strong 

 spine, which projects backward ; fore tarsi flattened, but scarcely 

 broadened. 



32. Crabro siugularis Sm. 



Crabro singularis Smith, Cat. Hym. Brit. Mus., iv, p. 417, % . 



Crabro quadrangularis Packard, 1. c, p. 85, 9 • 



Crabro singularis Packard, ibid. p. 86, % '$ . 



Crabro 14-macidatus Packard, ibid. p. 87, %, . 

 9 . — Head large, almost quadrate, finely and closely punctured, very closely so 

 in front ; space between eyes at base of clypeus somewhat greater than the width 

 of the latter in the middle ; first joint of flagellum distinctly longer than the 

 two fallowing united ; pronotum strongly furrowed on each side, dentate laterally, 

 punctate; meso- and metapleurie coarsely striated, the sides of middle segment 

 with the striae fewer aud coarser; middle segment above with the enclosure usu- 

 ally well marked, with coarse, longitudinal striae, the central furrow foveolate. 

 posterior face with irregular ruga;, the lateral ridges not at all developed. Black, 

 mandibles except apex, scape entirely or in part, two spots on pronotum, tuber- 

 cles, scutellum more or less, sometimes not at all spotted, sometimes the tips of 

 fore and medial femora, tibia; except within, first joint of tarsi, a long narrow 

 spot, pointed internally, on each side of abdominal segments 2-5, and sometimes 

 a small spot on each side of segments 1 and 6, yellow ; no silvery pubescence on 



TRANS. AM. ENT. SOC. XXII. JUNE, 1895. 



