Recorth of Bees. 129 



species. It was given to me by Mr. S. A. Rohwer, who had 

 already studied it and determined that it was new. 



Hah. Sugar Loaf Mountain, Boulder County, Colorado, 

 8500 ft.. May 18, 1907, at E.o\vev& of xbxtostaph^los uva-uasi. 

 Collected by Miss Edna Baker. 



Perdita quadrangular is, sp. n. 



cJ . — Length 4 mm. 



In my tables of Perdita runs to P. sphceralcece, of whicli it 

 looks like a small edition. From P. erigeronis it is easily 

 known by the pallid nervures and the coloration of the 

 abdomen. The face-markings are of a clirome-3'ellow 

 instead of lemon-yellow, but otherwise agree, as do all the 

 other markings of the head, with sphceralcece. The face 

 below the antennae is all yellow, the lateral marks being large 

 and quadrangular, ending on the orbital margin at an angle 

 of about 45°. Antennse chrome-yellow, the tirst four or five 

 joints black-spotted above. Thorax, legs, and wings essen- 

 tially as in sphceralcece, but margin of stigma yellowisii. 

 Abdomen with the venter yellow, as in spheralcece, but on 

 the dorsum the dark colour is reduced, the general effect 

 being that of equally broad light and dark bands, with tlie 

 apical segments a sort of yellowisii ferruginous. The thorax 

 has much wliite hair. 



Hah. Alamogordo, New Mexico, May 15, about eighty-five 

 specimens {H. L. Viereck). 



P. sphceralcece does not appear on the wing until long after 

 midsummer. 



Perdita Vierecki, sp. n. 



The female runs in the tables of Perdita to male P. tarda, 

 the male to P. exclamans. Both sexes were taken in large 

 numbers ; otherwise one would suspect the insect to be a 

 variety of P. exclamans, to which it is very closely allied. 



? . — Length about 4^ mm. 



Differing from exclamans as follows : — Size smaller ; 

 abdomen above piceous, with the yellow markings reduced 

 to a variable series of spots occupying the middle of the 

 segments ; thus the first segment may have a pair of dots or 

 no light marks at all ; the second may have a large quad- 

 rangular pale yellow patch or a yellow band on the middle 

 third ; the third segment, and also the fourth, may be more 

 or less banded, the band in no case approaching the lateral 

 margin ; or the fourth and fifth may each have a couple of 

 sj)ots ; thus the abdominal markings are extremely variable, 



Ann. d: Mag. N. Hist. Ser. 7. Vol. xx. 'if 



