1899.] >'ATURAL SCIENCES .OF THILADELPHIA. 65 



All the dorsal segments margiued apically with pale testaceous; 

 pubescence sparser, the sculpture of dorsulum and mesopleurffi 

 more or less obvious. Length 16 mm. 



margmata n. sp. (or var. of Morsei. ) 



3. Eyes strongly converging above: first joint of flagellum as long 



as four following united; abdomen pruinose above, especially 

 on first two segments, the others sparsely ; clypeus and labrum 



Avhite, Hofinannseggioi Ckll. 



Eyes not or scarcely converging above, 4 



4. Front broad, 5 



Front narrow, the distance between the anterior ocellus and 



apex of clypeus much greater than the greatest width of 

 front, 6 



5. "Scape wholly dark; mandibles dark reddish brown, with 



black tips;" legs dark, ccesalpinice Ckll. 



Scape beneath and mandibles more or less yellowish; legs red- 

 dish; abdomen, at least laterally, with bands of pale hairs 

 at apex of dorsal segments 2-4, .... rhodopus Ckll. 



6. Pubescence of thorax beneath dark brown or blackish, that on 



four hind legs entirely black; first joint of flagelfum shorter 

 than the following two united, .... atriventris n. sp. 

 Pubescence of thorax pale beneath, the medial tibise outwardly 

 and base of hind tibite externally with pale hairs; first joint 

 of flagellum nearly as long as the three following united, 



lanosa Cress. 

 1. Centris errans n. sp. 



?. — Head and thorax black; abdomen green-black, the apical 

 margin of segments 1-4, or 2-4, the remainder and ventral surface 

 entirely, an irregular mark on dorsals 2 and 3 laterally, tegulse 

 and the legs, reddish-brown, the anterior femora more or less black; 

 scape beneath, sometimes obscurely, base of mandibles, labrum, an 

 inverted T-shaped mark on clypeus, inner orbits as far as inser- 

 tion of antenna?, whitish yellow ; head with pale pubescence, that 

 on cheeks palest, the vertex crossed from eye to eye by a stripe of 

 black hairs; thorax above with pale fulvous pubescence, that on the 

 sides and beneath similar to that of the head in front; fore legs 

 fringed with pale hairs, the short pubescence fulvous; brush of hind 

 legs of a paler fulvous than the pubescence of thorax above; first 

 5 



