NORTH AMERICAN HYMENOPTERA. 267 



posteriorly, smooth ; flanks of mesothorax swollen ; wings as long as entire insect, 

 hyaline, iridescent ; marginal cell short, arcuate, lying almost entirely beneath 

 the stigma, which is large, lanceolate, fuscous, first submarginal as large as the 

 second and third together, second small, triangular, receiving the first recurrent 

 near the base, third subquadrate, receiving the second recurrent near the middle ; 

 tegulse honey yellow ; legs pale honey yellow, thinly clothed with yellow pubes- 

 cence ; abdomen elongate ovate, petiolate, petiole long, thinly clothed with white 

 hairs, second and following segments fuscous, with the apical margins dark honey 

 yellow, clothed with a few scattered hairs. Length 14-16 mm. 



Hiib. — Colorado. Two specimens. 



Allied to alcanor Bhike, but may be easily separated by the form 

 of the metathorax. 



Pliotopsis uitida Cresson. 



Male. —Pale chestnut brown, polished, very sparsely punctured, clothed with 

 a long, scattered, pale pubescence ; antennte and tegulte pale testaceous ; post- 

 scutellum with a central pit; disk of metathorax with a shallow, longitudinal 

 depression, slightly striated at base ; wings hyaline, faintly tinged with yellow- 

 ish ; nervures and stigma fuscous; marginal cell very short, appendiculated at 

 tip; second submarginal cell triangular, petiolated ; third submarginal cell large, 

 subquadrate ; abdomen very feebly punctured ; basal segment petiolate, gradu- 

 ally dilated to tip ; disk faintly sulcate ; venter tinged with fuscous. Length 

 11-14 mm. 



Hab. — Colorado. Lieutenant C. W. Whij^ple. 

 This is allied to Pi alcanor Blake. 



Photopsi$$ alcauor Blake. 



Male. — Head black, rounded, wider than the thorax, very finely punctured, 

 mandibles black, tridentate at tips ; eyes very large, prominent ; ocelli also large ; 

 antennte fulvo-testaceou-s, more than half as long as entire in.sect, the joints 

 curved, presenting a slightly scolloped appearance when viewed laterally ; thorax 

 chestnut lirown, elongate subquadrate, truncate in front, di.sc of mesothorax sub- 

 convex, shining, feebly and remotely punctured, with two lateral, longitudinal 

 impressed lines, the lateral lobes finely and closely punctured, metathorax trun- 

 cate, shining, the dorsal groove extending to apex ; wings pale yellowish hyaline, 

 nervures pale fuscous; stigma large, marginal cell short, roundly obliquely trun- 

 cate at tip, three distinct submarginal cells, the first nearly as long as the stigma 

 and marginal cell combined, dilated towards the base, second subtriangular, 

 truncate at base and lying entirely beneath the first, receiving the first recur- 

 rent beyond the middle; legs castaneous, thinly clothed with pale hairs, more 

 dense on the tibiae and tarsi ; abdomen elongate, petiolate, chestnut brown, 

 shining, petiole pyriform, minutely punctured, punctures coarser about the apex, 

 second and following segments feebly punctured and sparsely clothed with scat- 

 tered pale pubescence. Length 13 mm. ; expanse of wings 23..5 mm. 



Hab. — Arizona. 



This species resembles P. castanea Cresson, but may be known by 

 the greater length of antennse and the head being entirely black. 



