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



9 . Head more cubical, eyes reaching one-half back to hind edge; 

 front edge a little broader ; tip acuminate, abdomen broader and 

 shorter. 



The smallest genus of the group, except Spilomcna, which has a 

 sessile abdomen. It is closely allied to Rliopahtm; in neuration more 

 like Cemonus than Pcmphredon. It differs from both in its minute 

 size. It will at once be recognized, as its name indicates, by its very 

 large pterostigma, the small 3d costal cell, the elongated propodeum, 

 with its sculpturing and obsolete enclosure ; its long, narrow abdomen, 

 and minute scarcely grooved tip. The species differ in very slight 

 characters, such as the proportions of the front of the head, and the 

 sculpturing of the propodeum, and all have the white "tubercle" on 

 the flanks of the mesothorax very distinct. 



Stigmus americanus, n. sp. 



9 . Head black; impressed line in front of the ocelli well marked; 

 clypeus and lower part of the orbits silvery pubescent ; mandibles 

 whitish-yellow; tipspiceous; antennas brown above, beneath testaceous 

 on the basal half. Prothorax sharply crested on the posterior margin, 

 convex ; notuui behind the crest longitudinally striated ; meso-scutum 

 smooth and polished; tubercle testaceous yellow; scutum and meta- 

 scutellum smooth. Propodeum covered with a loose irregular net-work 

 of shallow fossae, bordered by thin ridges; mesial furrow only present 

 posteriorly where it expands into lozenge-shaped fossae ; flanks of tho- 

 rax striated, the two most prominent convexities on the flanks of the 

 mesothorax smooth and polished ; tegulae and base of wings pale testa- 

 ceous. Nervures brown, fore and middle legs testaceous, femora a lit- 

 tle darker, all the coxae and trochanters testaceous at tip ; hind femora 

 brown, tibife fusco-testaceous at both extremities; tarsi pale testa- 

 ceous. 



Abdomen with a long pedicle, longer than head and thorax together, 

 body of the abdomen a little longer than the thorax ; pedicel grooved 

 above aud laterally ; body of abdomen narrow, ovate, slightly contracted 

 at hind edge of 2d ring of abdomen; smooth and slightly polished; 

 extreme tip rufous. 



Length, .16 inch. 



Illinois, (Coll. Ent. Soc. Phil.; Norton). 



This species is closely allied to, and represents S. pendulus of Eu- 

 rope. The antennae are, however, paler, the basal joints of legs much 

 paler, while the sculpturing of the propodeum is very different. 



