NORTH AMERICAN HYMENOPTEKA. 315 



Four hind tibiee medially and the fore tibiie behind, blaek ; nietanotuni with 



strong fossulets. Length 6 mra Gillettei. 



3. "Mandibles white, reddish at tip; dorsiiluin more densely and minutely 

 punctured anteriorly than on the disc" Hineri<*aiiiis. 



Mandibles black ; dorsulum densely punctured apically iiigrituiii* 



MALES. 



1. Joints 9-12 of the autenme serrated beneath; mandibles yellowish 2. 



Joints 9-12 of the antennae not serrated beneath ; mandibles lilack ; rilii;i- ;ind 



tarsi yellow flavitai'Mi<<$. 



2. Metanotum rather finely rugose; tibiiv more or less black. ..wccideiitali!^. 

 Metauotum strongly rugose or rugged ; tibia; entirely yellow rugO!i»us. 



1. Diodoiitiis occideittalis n. sp. 



9- — Emargination of labrum deep and wide, forming two very acute teeth; 

 front shining, distinctly but sparsely punctured, the longitudinal impressed line 

 strong; mandibles and clypeus with sparse, long, pale hairs; cheeks punctured 

 like the front, the vertex and occiput much more closely punctured ; ocelli situ- 

 ated in slight pits; dorsulum distinctly punctured, the punctures more close 

 anteriorly; scutellum punctured like the dorsulum strongly impressed down the 

 middle; mesopleursB and metathorax rugose, the metanotum indistinctly en- 

 closed, without a longitudinal furrow ; collar and prothorax on sides with coarse, 

 oblique striations. Wings hyaline, nervures testaceous, stigma black ; femora 

 glabrous, the tibife armed with bristle-like spines. Abdomen shining, with ex- 

 ceedingly close and fine punctures; ventrally the punctures are coarse and 

 sparser ; pygidiura triangular, with large, sparse punctures. Black ; abdomen with 

 sericeous pile; face on sides in certain lights silvery; mandibles, except tips, 

 tegulse, tubercles, tibiae and tarsi yellowish, the apical portion of the tarsi darker. 

 Length 5 mm. 



% . — More elongate than the female, emargination of labrum not so wide and 

 deep, the teeth formed by it obtuse; front subopaque, very densely punctured, 

 having the appearance of being granulose, not impressed down the middle; 

 vertex and occiput with distinct separated i)unctures; antennae almost filifoin), 

 joints 3-5 about equal in length, joints 6-11 also about equal, but are longer 

 than 3-.5, the twelfth shorter than the eleventh, the last one fully as long as the 

 scape, joints 9-12 serrate beneath ; dorsulum just before scutellum very closely 

 punctured ; scutellum not so closely punctured as the dorsulum, not impressed 

 medially. Black ; mandibles, except tips, spot on tegulae, fore tibiae in front, the 

 remaining tibiw, except a black line within, and tarsi, except apical portion, 

 yellowish. Length 4 — 5 mm. 



Southern California ; Arizona. Seven specimens. 



2. Dio<loiitiis riiso<«ii!« u. sp. 



%. — Kot elongate, of the same form as the female of occidentalis ; emaririna- 

 tiou of labrum wide, but not deep; front subopaque, densely punctured, but has 

 not the apjiearance of being granulose; the ocelli situated in pits, that which 

 contains the anterior one most distinct ; vertex and occiput with distinct sepa- 

 rated i)unctures; antenim^ slightly setaceous, joints Sand 4 united a little shorter 

 than the fifth and sixth, which are, if anything, a little longer than the seventh 



TRANS. AM. KNT. SOC. XIX. DKCEMBEK, 1892. 



