56 PROCEEDINGS OF THE ACADEMY OF [1896.. 



anterior third, which is sparsely hairy and punctured. The thorax 

 shines distinctly blue in ventralis $ , but in the 9 it hardly goes off 

 a pure black. The $ resembles californica in its face-markings, 

 but is so much smaller, and the dog-ear marks are much more 

 prominent. The vertex is minutely roughened in the same way in 

 $ and 9 . 



The face in the 9 is all dark, not so in the $ . The S has the 

 lateral face-marks much broader than long, the dog-ear marks well- 

 developed, but the supraclypeal mark represented only by a dot 

 adjacent to each dog ear mark. 



It is to be regretted that ventralis is the only undoubted member 

 of the californica group of which we know the 9 • The-sexual dif- 

 ferences in Perdita are very unequal in the different species, whether 

 occurring as face-markings or as structural characters. In the un- 

 doubted sexes of P. verbesuue, the elypeal differences are not so great 

 as in ventralis, but the difference in the mandibles is actually much 

 greater. 



7. Perdita mexicanorumn. sp. 



$ . — Length about 5J ram. Head and thorax dark blue. Head 

 rather large, cheeks unarmed, clypeus panama-hat shaped, glossa 

 very long and unusually hairy. Cheeks and face very sparsely hairy 

 with short hairs. Vertex strongly granular, and with rather close 

 but shallow punctures. Antennae entirely sepia-brown, the same 

 color above as below. Mandibles yellowish, subtestaceous, dark at 

 tips, simple, not particularly slender. Face-markings sulphur-yellow ; 

 clypeus yellow with the usual two black dots very small and near 

 the edge, and its proximal margin (the crown of the panama-hat) 

 broadly dark, the edge of the yellow somewhat irregular and medi- 

 ally emarginate. Supraclypeal and dog-ear marks absent. Sides of 

 face with large squarish yellowish patches, their upper margins 

 truncate and rather irregular, about level with the top of the clypeus. 

 Inwardly, these patches do not join the elypeal margin, but leave a 

 thin wedge of dark color between. 



Thorax dark blue, the mesothorax slightly inclined to greenish. 

 Prothorax and tubercles entirely dark ; postscutellum sulphur- 

 yellow. Mesothorax moderately shining, but distinctly granular 

 and punctuate, median groove distinct. Metathorax shining but 

 very distinctly granular. 



Tegulse testaceous ; wings slightly smoky, nervures and stigma 

 dull brownish-ochreous, stigma not centrally hyaline. Marginal 



