no. 2064. BEES OF GENUS ANDRENA—VIERECK AND COCKERELL. 33 



I could not distinctly separate two species, though some were con- 

 sidered to be ribifloris, and one was determined as Jiemileuca by Mr. 

 Viereck. In the present paper I give characters to separate the 

 described specimens of Jiemileuca and ribifloris, but the matter 

 needs further investigation. In the key, they separate on the char- 

 acter of the antennae, Jiemileuca having the third joint shorter than 

 the fourth, which is not true of ribifloris.) 



6 39 . Second submarginal cell receiving first recurrent nervure at or near middle. 

 a 41 . Cheeks strongly angled behind; abdomen not evidently banded. 



ANDRENA ENIGMATICA, new species. 



Lincoln, Nebraska. April 25, 1901. On willow. (M. A. Car- 

 riker.) 



Male. — Length, 8£ mm. Black, slender, with long pale hair dis- 

 tinctly tinged with ochreous on scutellum; some fuscous hairs at 

 sides of front. Head large and broad, facial quadrangle very much 

 broader than long. Mandibles long and slender, curved downward, 

 red at apex; process of labrum truncate; clypeus moderately shining, 

 with rather shallow punctures; sides of front dull and finely striate. 

 Antennae long and slender, flagellum obscure brown beneath. Third 

 antennal joint not quite twice as long as fourth; fourth longer than 

 broad; fifth conspicuously longer than fourth. Cheeks shining, very 

 broad, triangular, produced to a right angle behind. Mesothorax 

 dull and granular. Scutellum shining in front. Metathorax granu- 

 lar, the area very small. Wings hyaline, dusky at apex, stigma and 

 nervures dull amber. Basal nervure falling short of transverse 

 median. Second submarginal cell broad, receiving first recurrent 

 nervure beyond middle. Hind legs long and slender. Abdomen nar- 

 row, shining, impunctate, with scattered pale hair not forming well- 

 defined bands. Hind margins of segments obscurely reddish. 

 Second segment in middle depressed less than a third. Apical plate 

 rather broad, not emarginate. 



Ty^-— Entomological collection of the University of Nebraska. 



In the key, this falls close to A. moesta albihirta, from which it is 

 known by the absence of black hair on the cheeks. 



ft 41 . Cheeks not angled behind; abdomen subfasciate. 



a 42 . Fourth anntenal joint conspicuously longer than broad; hair of face creamy white; 

 basal nervure falling short of transverse median. 



ANDRENA CANDIDIFORMIS, new species. 



Colorado. (Gillette, No. 2112.) 



Male. — Length, 7 mm. Black; small joints of tarsi ferruginous; 

 hair grayish white, pale ochreous on thorax above, black at sides of 

 front. Head broad but otherwise ordinary. Facial quadrangle 

 much longer than broad. Process of labrum broad, truncate; man- 



59758°— Proc.N.M.vol.48— 14 3 



