408 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



hair very long and contrasting with light hair of clypeus. Tem- 

 ples and mesopleura with much black hair. Disk of mesoscutum 

 and scutellum with a few shorter black hairs intermixed. Process 

 of labrium about twice as broad as long, truncato-emarginate at 

 apex. Clypeus not depressed, dullish, closely and shallowly punc- 

 tured. Antennae extending slightly beyond base of propodeum, 

 the flagellum not at all reddened. First joint of flagellum nearly 

 equaling joints 2 and 3 together. Joint 2 as long as wide, the fol- 

 lowing joints somewhat longer than wide. Genitalia nearly as in 

 chlorura, but the sagittae slightly less broadened across the basal 

 part. Length 7-8.5 mm.; anterior wing 5.6-6.5 mm. 



Types.— U.S.^M. No. 59285. Holotype (female), Stanford 

 University, Calif., March 5, 1906 (J. M. Aldrich) and 5 other 

 females (paratypes), from Stanford University, February and 

 March (Aldrich and H. Morrison) , 2 of these from wild mustard. 

 Allotype, in the collection of the Citrus Experiment Station, from 

 Berkeley, February 16, 1935 (R. M. Bohart). 



Paratypes: In the collection of the Citrus Experiment Sta- 

 tion, 1 male, 6 females, Berkeley, February and March 1934 and 

 1935 (R. M. Bohart) ; in the collections of the University of 

 California at Berkeley and of Dr. U. N. Lanham: 2 males, 1 

 female. Grizzly Peak Boulevard, Berkeley, February 15, 1939; 

 5 females, Berkeley, on Brassica, March 6, 1947 (J. W. McSwain) ; 

 and 11 females, Berkeley, on Brassica, March 12, 1947 (U. N. 

 Lanham) . 



ANDRENA (THYSANDRENA) DISSIMULANS. new species 



This is a small green fasciate species of Thysandrena, similar 

 to A. suavis Timberlake, but distinguishable by having the facial 

 foveae broader, the tibial scopa weakly plumose, and the middle 

 basitarsi no wider than the hind pair. The male is easily separated 

 from suavis by having antennal joints 3 and 4 subequal in length. 



Female. — Dark green ; the labrum, anterior margin of clypeus> 

 mandibles, antennae, and legs, black. Mandibles dark red on 

 apical half. Flagellum reddish brown beneath, except toward 

 base. Legs slightly brownish, the small joints of tarsi, especially 

 the apical joint, ferruginous. Tegulae testaceous brown, paler 

 at apex. Wings strongly dusky, the stigma and nervures dark 

 reddish, the subcosta piceous. Head much broader than long, 

 the eyes slightly convergent below. Process of labrum rather 

 small, with sloping sides and broadly truncate to rounded apex. 

 Antennal joint 3 barely longer than the next two ioints together. 

 Facial foveae dark brown above, appearing whitish below when 

 viewed from behind, moderately narrow, short, contiguous to eye 

 margin and ending distinctly below level of anterior ocellus and 

 thus widely separated from the lateral ocelli. Head and thorax 



