SOUTHERN CALIFORNIA ACADEMY OF SCIENCES. 5 



stripes on margin of niesotliorax are not bent posteriorly, the 

 anterolateral spots on sciitellum are wanting, the abdominal 

 bands on the third and following segments are somewhat more 

 widely interrupted, and are laterally very deeply incised or di- 

 vided altogether, those on four and five always being divided; 

 the sixth segment has much black, being in the female black 

 with two yellow marks, and in the male usually yellow with a 

 reversed black T ; ventral scopa white ; legs in female black, the 

 apices of femora, tibiae and tarsi ferruginous ; anterior tibae 

 with more than the basal half yellow outside, middle tibiae all 

 yellow outside, hind tibiae with a yellow basal spot ; in the male 

 the anterior and middle legs are strongly bearded with long 

 vvhite hair, the anterior tibiae are yellow outwardly and pale 

 reddish within, the middle tibiae are yellow with a very large 

 black spot on the outer surface and a similar reddish one on the 

 inner, and the hind tibiae are black with the ends broadly yel- 

 low, the tarsi have the basal joint yellow and the small joints 

 ferruginous ; the apex of the male abdomen is truncate with a 

 faint trilobation. 



Dianthidium consimile (Ashmead.) 



Dr. Davidson sends me three collected at Los Angeles; they 

 bear dates June 13 and 15. I have identified the species from 

 Ashmead 's description, but I find that this, although stated to 

 be that of a female, accords with the male of the insect before 

 me. In the female the clypeus is black in the middle and yellow 

 only at the sides. Except for this discrepancy the description 

 applies excellently. The yellow tooth or spine on the hind 

 coxae is very small in the female, somewhat larger in the male. 

 Dianthidium davidsoni, n. sp. 



Two males collected by Dr. Davidson at Bear Valley, Cali- 

 fornia. 



Length 8 to 9 mm. ; black with bright chrome yellow mark- 

 ings. In structure and markings similar to D. parvum, but 

 larger, with the yellow much brighter, and the abdominal bands 

 much less incised. The pubescence of the upper part of the 

 head and thorax has a yellowish tint. Apical segment of abdo- 

 men yellow, truncate and faintly trilobed, only its extreme 

 base, where it is overlapped by the penultimate segment, is 

 black; penultimate segment yellow except the overlapped base, 

 a median basal pointed process, and two transverse subapical 

 marks (in parvum it is black with two light yellow crescents 

 joining medially) : first recurrent nervure about as far from 

 base of second submarginal cell as the second is beyond its 

 apex ; yellow spines of hind coxae very large ; pleura with or 

 without a small yellow spot. 



The following species, hitherto placed in Anthidium, must be 

 transferred to Dianthidium, D. formosum (Cress.), D. gabbi 



