18b9.] NATURAL SCIENCES OF PHILADELPHIA. 67 



of the " Palo Verde," Parkinsonia Torreyana. Dr. Griffith states 

 the bees were alnmdant and easily captured, allowing the collecting 

 bottle to be slipped up quite close to them and the stopper then 

 used in such a manner as to knock them into the bottle. This 

 apparent lethargic condition of the specimens is quite unusual for 

 species of Centris, as from all accounts they are usually very rapid 

 flyers and easily disturbed, after the manner of Odonata. I can 

 testify from experience as to the alertness of two of the West In- 

 dian species, C. hcemorrhoidalis and C. fasciata. The abdomen is 

 densely pruinose a])ove, 



3. Centris Morsei Ckll. 



Centris Morsei CockereU, Proe. Acad. Nat. Sci. Phila., 1897, 355, (^. 

 New Mexico: Mcsilla. Quite distinct by its large size (21 mm. ) 

 and the pale reddish-yellow bands on dorsal segments 1 and 2. 



4. Centris marginata n. sp. 



rj. — Black; ventral segments laterally testaceous-yellow, all the 

 dorsals at apex broadly margined with testaceous; flagellum 

 slightly brownish beneath ; clypeus, labrum and spot between an- 

 tenna at base of clypeus, bright lemon-yellow; mandibles reddish- 

 brown, with black tips; entire insect covered with pale gray pubes- 

 cence, except the abdomen above, which is quite bare, excepting 

 the extreme base of first segment; the pubescence inclining to 

 fulvous on top of head and thorax, and sufficiently thin on dorsu- 

 lum and mesopleurse to display the sculpture; front broad; first 

 joint of flagellum about as long as the three following united; legs 

 robust; pubescence of anterior tibite and tarsi internally reddish- 

 brown, that on first joint of hind tarsi internally, dark; wings 

 subhyaline, nervures blackish. Length 16 mm. 



New Mexico: " Las Cruces (August 23) on flowers of CevaUia 

 dnuata.'" One specimen received from Mr. Cockerell and bearing 

 the label " C. ccesalpinice cf," which name was probably attached to 

 it by error, as it neither agrees with the description of the male of 

 C. ccesalpinice, nor is it even closely allied to the female of that spe- 

 cies. Its affinities ai-e to C. Morsei, from which it does not difier 

 structurally. 



5. Centris caesalpiniae Ckll. 



Centris cmsalpinice Cockerell, Ann. and Mag. N. H., Ser. 6, xix, 394, 

 ? d, 1897. 

 New Mexico : Las Cruces. I have not seen the male of this 



