THE CANADIAN ENTOMOLOGIST. 393 



NEW NORTH AMERICAN BEES. 



BY T. D. A. COCKERELL, UNIVERSITY OF COLORADO. 



M ditto. Willardi, n. sp. (Fossil.) 

 $ . — Thorax and legs apparently black; tegulse pallid; thorax robust, 

 5 mm. wide ; scops, of hind tibia and basitarsus abundant, coarse ; no 

 floccus at base of hind legs ; hind femur about 2^ mm. long, tibia about 

 3, basitarsus about 2 ; middle tibia short and very broad, about 1700 fi 

 long and 850 broad at end. Anterior wings about 9 mm. long, hyaline, 

 stigma and nervures pale brown ; stigma long and narrow, but very 

 distinct ; venation normal for Melitta ( e. g., M. leporina), except that the 

 upper segment of the basal nervure is shorter ; in the description here 

 given all the measurements are in microns. 



Marginal cell 2414 long, 629 deep, pointed on costa ; stigma 340 

 deep ; three submarginal cells, the first much the longest, the second much 

 the shortest, and receiving the first recurrent nervure at about the end of 

 its first third ; length of first submarginal from lower basal to upper 

 apical corner 17 17, from lower basal to lower apical coiner (not allowing 

 for curve) 1530; length of second submarginal above (on marginal) 408, 

 below (measured in a straight line from corner to corner) 493 ; second 

 submarginal on first discoidal 187, on third discoidal 340 ; third sub- 

 marginal cell on marginal 374, on third discoidal 680, its total length 952, 

 the distance from second recurrent nervure to apical appendiculation 221; 

 third transverse-cubital nervure with its upper part, before the strong curve, 

 nearly straight ; total length of first discoidal cell (lower basal to upper 

 apical corner) 2805 ; outer side of third discoidal practically straight (as 

 in Andrena, etc.) ; basal nervure on first submarginal cell 374, on first 

 discoidal 1241 ; basal nervure meeting transverso-medial, the latter 

 oblique, the lower end more apicad. 



Hab. — Fossil in the Miocene shales of Florissant, Colorado ( Willard 

 Rusk, 1909). The reference of this insect to Melitta seems safe ; the 

 hind legs are so preserved that a floccus would be visible on the 

 trochanters were it present ; and the form of the stigma, the proportions 

 of the submarginal cells, and the second submarginal receiving the 

 recurrent nervure well before the middle, are all extremely characteristic. 

 Melitta is a rather isolated and probably ancient genus, with few living 

 species, all palaearctic except three, two in the north-eastern United States, 

 and one in Lower California. 



November, 1909 



