NORTH AMERICAN HYMENOPTERA. 201 



nervures and stigma brownish. Black ; mandibles, and legs sometimes, rufotes- 

 taceous; extreme base and apex of scape and first two joints of medial and fore 

 tarsi, pale yellow; tegulse pale testaceous; clypeus, inner orbits beneath and 

 cheeks with silvery pubescence ; thorax on sides and beneath and legs with silvery 

 sericeous pile, which is more obvious in certain lights. Length 8 mm. 



% . — Clypeus less distinctly produced medially, antenna> simple: first joint of 

 medial tarsi simple; abdomen, scape in front, ajiex of medial and the fore tibiai 

 anteriorly, and their tarsi entirely, pale yellow. Length about 7 mm. 



Nevada. Four specimens labeled Rliopalum occideidale Cress., 

 evidently a manuscript name only. Its larger size will distinguish 

 it from the species of the 2:)receding or the following group. 



23. Group pedicellatas. 

 The two species composing this group are distinguished from the 

 three preceding groups as follows : pygidium ( 9 ) narrow, excavated 

 its entire length ; anterior margin of clypeus angularly produced. 

 This is the only group having a petiolated abdomen, in which the 

 % antennae are dentate or lobate beneath. 



91. Crabro pedicollutiis Pack. 



Rhopalum pedk-eUatnm Packard, Proc. Ent. Soc. Phila., vi, p. 3a0, \, J . 



9 . — Clypeus subconvex, with anterior margin acutely and angularly produced 

 in the middle, and on each side with a small tooth ; head finely and evenly punc- 

 tured ; ocelli in a triangle, a depression on the vertex on each side of the poste- 

 rior pair, which extends to the inner orbits ; frontal depression broad and polished, 

 a narrow impressed line extending fi-om it to the fore ocellus; second joint of 

 flagellum nearly three times longer than the first, which is a little more than half 

 as long as the pedicellum; thorax punctured about like the head ; enclosure at 

 base of middle segment semicircular and distinct, and divided by a longitudinal, 

 strongly impressed line, which extends down on the posterior face in the form of 

 a deep and wide furrow, the sides of the posterior face ridged; legs robust, par- 

 ticularly the hind i>air, the four hind tibise strongly spinose, and the posterior 

 pair strongly serrated in addition ; first segment of abdomen above grooved on 

 basal half, the posterior portion enlarged and glabrous, in length somewhat longer 

 than the second segment; pygidium strongly concave or excavated ; wings hya- 

 line, strongly iridescent, nervures and sdgma black. Black ; scape, tubercles, all 

 the coxae and trochanters, the apical portion of femora, except hind pair, the fore 

 tibise entirely, the four hind tibiaj at base and the fore and medial tai'si, pale yel- 

 low; mandibles yellowish testaceous; flagellum dark fuscous, paler beneath; 

 tegulse and pygidium testaceous; clypeus, inner orbits below, cheeks and thorax 

 beneath less densely, with silvery pubescence. Length 5-6 mm. 



% . — Clypeus large and broad, the lateral portions of the anterior margins 

 slightly revolute. the produced medial portion obtuse atapex : antennse 13-jointed ; 

 second joint of flagellum twice as long as the third, narrowed basally. and de- 

 veloped into a lobe on apical portion beneath ; third joint as long or longer than 

 the following two united, also much narrowed basally ; basal joint of medial tarsi 

 laminate within ; hind tarsi somewhat flattened, the basal joint curved, and 

 much broadened apically ; abdomen longer and narrower than in the 9 ! hind 

 femora testaceous at apex, not serrate or strongly spinose ; otherwise like the 9 • 



TRANS. AM. ENT. SOC. XXII. (20) JUNE, 1895. 



