294 



H. Friese. 



females for the very different males of these species. The female lanosa, however, 

 average decidedlv larger than the Hoffmansegs:iae, and the second abdominal segment, 

 as well as the first, is delicately pruinose. The claws also are noticeably larger and the 

 black Upper margin of the clvpeus is broader, so that the yellow or orange is reduced 

 to the shape of a half-circle. 



The following tables mav be found convenient: 



Females. 



[Clypeus schwarz birkmanni Friese.] 



Clypeus crimson i. 



Clvpeus yellow or orange, its upper border more or less black 2. 



1. Length over 14 mm.; legs black caesalpiniae Ckll. 



Length under 14 mm.; femora and tibiae rufous . . . rhodopiis Ckll. 



2. Second abdominal segment pubescent lanosa Cr. 



Second abdominal segment bare hoffmanseggiae Ckll. 



Males. 



Front broad i. 



Front narrow 2. 



1. Length over 14 mm.; scape without vellow .... caesalpiniae Ckll. 

 Length under 14 mm.; scape vellow in front .... rhodopus Ckll. 



2. Abdomen with narrow hair-bands; clvpeus vellowish white hoffmanseggiae Ckll. 

 Abdomen without hair-bands; clvpeus lemon-yellow. . lanosa Cr. 



Mr. Fox has suggested (Proc. Cal. Ac. Sei., i8g3, pag. 22) that lanosa is very likelv 

 identical with mexicana Smith. C. mexicana was described from a female, wdiich is at 

 all events quite different from that which I have here referred to lanosa. I am much 

 indebted to Mr. L. O. Howard for sending me copies of a number of descriptions of 

 Centris to which I had not access.« 



Centris lanosa wurde von Cockerell näher bekannt gemacht; ich verdanke ihm 

 ein Pärchen von Mesilla (N.-Mexico), i3. Mai (vgl. Anhang). 



79. Centris caesalpiniae Cockll. 



1897. Centris caesalpiniae Cockerell, d" $, Ann. and Mag. Nat. Hist. (6), XIX, pag. 894. 

 »9. Black; head and thorax with pale ochraceous pubescence, short and very 

 dense on thorax, clypeus and sides of front bare. Eves, clypeus, labrum, and basal 

 three fifths of mandibles crimson. Clvpeus shining, verv sparselv punctured. Mandibles 

 truncate at tips and with four denticles, alternating large and small, on inner side. Some 

 very long hairs spring from near the base of the mandibles beneath. Antennae black, 

 the end of the scape slightly tinged with rufous. Front very broad, inner orbits parallel. 

 Tegulae whitish. Wings smoky hyaline, nervures and Stigma fuscous, third sub- 

 marginal cell narrowed more than half to marginal, no distinct stump of a nervure 

 springing from lower outer corner of third submarginal. Legs black or dark piceous, 

 with black pubescence, and more or less pale brownish pubescence on the four anterior 

 legs; hind tibiae and basal Joint of tarsi broadly dilated, with dense black hairs. Claws 

 large, rufous at base, seeming to be entire, but when seen from above a small denticle 

 is visible on the inner side. Abdomen almost bare, what little pubescence there is 

 black, except some pale pubescence at base of first segment. Apex with verv dark 



