inO Mr. T. D. A. Cockerell — Descriptions and 



but in all cases the colour is very different from that of 

 exclamans, which has broad yellow bands, mostly reaching 

 the lateral margins. 



^ , — Essentially as in exclamans, but the head-like ex- 

 tension of tlie yellow above the antennae in middle line is 

 much smaller, and the yellow patch on the pleura does not 

 send a band to the middle coxaj. 



Ilah. Alamogordo, New Mexico, April 2G to May 15, 

 about 110 specimens {H. L. Viereck). 



Although this series is manifestly distinct from P. excla- 

 mans, some of the specimens show more or less evident 

 transitional characters, suggesting that the insect should 

 perliaps take only subspecific rank. This is one of tiiose 

 cases, of whicli we now know several in Perdita, which 

 promise to yield facts of extreme interest to the evolutionist 

 when carefully studied in the field. 



Perdita phacelia^, Ckll. 



Alamogordo, New Mexico, May 13 and 15 and June 6, 

 33 specimens (/7. L. Viereck). 



I have compared tiie Alamogordo specimens with cotypes 

 of 'phacelim and cannot see any difference. The latter, 

 however, were taken early in September. Are we to suppose 

 that this species winters over in the adult state, or is it 

 double-brooded? The small size and dull mesothorax readily 

 separate this from P. ceneifrons. 



Perdita i^ectidis, Ckll. 



This also has been known as an autumn species, flying in 

 September. Mr. Viereck took at Alamogordo, April 24 and 

 May 3, a series of about 65 specimens, which exhibit much 

 variation, but do not seem to be separable from P. pectidis. 



In the female the clypeus may be three-spotted or may 

 lack the middle spot, and even tlie lateral spots may be very 

 small. The banding of the abdomen varies from a couple of 

 dots only to well-developed bands. In general, however, the 

 insect agrees excellently with pectidis, and I do not think it 

 possible to regard it as distinct. 



Perdita cJiamasarachoi, Ckll. 



Highrolls, New Mexico, June 11, 1902 {H. L. Viereck). 

 T'his species was found flying at Albuquerque and Santa Fe 

 in August. 



