PRIOCNEMIS. 157 



domcu subpetiolato, the first segment being gradually widened from 

 the base. 



Hah. Costa Rica, Irazu. 



2. Pepsis optimus. 



Female. Length 21 lines. — Blue-black, brightest on the abdomen, 

 which is adorned with violet and purple tints. The anterior 

 margin of the clypeus widely, but slightly emarginate ; the scape 

 and the first joint of the flagellum and the base of the second black, 

 the rest of the joints bright yellow ; the head thinly sprinkled with 

 black hairs. The thorax velvety ; the metathorax with a central 

 longitudinal channel, and at its base a few transverse carinje, there 

 are also a few at the sides near the verge of the truncation ; wings 

 ferruginous, blackish at the extreme base of the anterior pair, their 

 apical margins not clouded ; the norvures, except the costal and 

 the others towards the base of the wings, ferruginous ; legs of a 

 purple-blue and thickly spinose. 



Male. Length 13 lines, — Of the same colour as the female, but 

 has the flagellum of the antennse of a reddish yellow ; it has also 

 a small subhy aline spot at the base of the second discoidal cell, and 

 the extreme apex of the anterior wings is narrowly subhyaline. 



Hab. Costa Eica, Irazu, 6000-7000 feet, and river Susio. 



This appears to be an undescribed species. It is most nearly allied 

 to P. montezuma, but is at once distinguished by the yellow antennae 

 in both sexes, and by the wings not having a fuscous margin or 

 broad black basal one. 



PRIOCNEMIS, Dahlb. 



1. Priocnemis laevis. 



Female. Length 8| lines. — Elack; the head and thorax opaque, 

 the abdomen impunctate, smooth and shining ; wings flavo-hyaline, 

 the nervures ferruginous. The front below the antenna? and 

 the cheeks with short downy golden pubescence, the latter have 

 also a thin long fulvous pubescence ; the mandibles pale testaceous, 

 with their base and apex black ; anteiime black. Thorax with the 

 sides, beneath, the coxae, and femora with golden downy pile ; the 

 tibiae, tarsi, and tips of the femora ferruginous, more or less fuscous 

 above ; the metathorax smooth, the sides and apex (and probably in 

 some specimens entirely) clothed with golden- coloured pile. The 

 apical segment of the abdomen with short rufo-fuscous pubes- 

 cence ; beneath, the apical margins of the third, fourth, and fifth 



l^segments are narrowly rufo-testaceous. 



Ilab. Costa Rica, Irazu, 6000-7000 feet. 



