80 Mr. F. Smith on some new Genera and Species 



Family Pompilidae, Leach. 

 Genus Planiceps, Latr. 



1. Planiceps concolor. 



P. nigro-violacea, sericea et iridescens ; alis anticis nigro-purpureis mi- 

 cantibus, alis posticis pallidioribus viridi-tinctis. 



Female. Length 5 lines. Deep blue, with brilliant reflexions in dif- 

 ferent positions; the mandibles obscurely ferruginous; the antennae 

 black. Thorax : the wings beautifully iridescent, the anterior pair dark 

 brown, the posterior pale fusco-hyaline ; the anterior tarsi rufo-testa- 

 ceous, the intermediate tibia3 and tarsi slightly spinose. The abdomen 

 of a smooth shining iridescent blue. 



Hub. Mexico. 



All the species of the genus- Planiceps are insects of great rarity : 



four have been previously recorded ; the two described in the present 



paper are, perhaps, the most beautiful that have been discovered. 



2. Planiceps notahilis. 



P. nigerrima, sericea ; abdomine supra plagis quinque albido-luteis notato, 

 2-2L ; alis nigris, vix iridescentibus. 



Female. Length 1\ lines. Black, subopake, and covered with a fine 

 silky silvery pile ; that on the vertex and disk of the thorax has a purple 

 iridescence ; the mandibles obscurely ferruginous at their apex ; the 

 scape of the antenna? compressed ; the posterior ocelli situated on the 

 posterior margin of the vertex. Thorax : the wings very dark brown 

 and slightly iridescent ; the intermediate and posterior tibia; and tarsi 

 slightly spinose. Abdomen : a large subovate yellowish-white spot on 

 each side of the second and third segments, and a single one at the base 

 of the apical segment. 



Hub. Mexico. 



Family Nyssonidae, Leach. 



Genus Pison, Spin. 



1. Pison maculipennis. 



P. niger, subtiliter punctatus, sericeo-pubescens ; eapite antice aureo- 



villoso; thorace, pedibus abdominisque segmento primo et secundo 



ferrugineis ; alis hyalinis, maculis fuscis. 



Female. Length 4-J- lines. Head black, the face densely covered with 

 golden pubescence; the scape, three basal joints of the flagellum, the 

 clypeus and mandibles ferruginous. The thorax, legs and abdomen 

 with a pale silky pubescent pile ; the thorax ferruginous as well as the 

 legs ; the post-scutellum and sides of the metathorax black ; the apical 

 joints of the tarsi slightly fuscous; the wings hyaline, the externo- 

 medial and the marginal cells occupied by a dark-fuscous cloud, the 



