June, I9I5.] AlDRICH : BlOLOGY OF WESTERN EpHYDRA. 97 



luster, the tibiae yellow with infuscated tip, the tarsi infuscated. The 

 average of size is slightly larger, and the hairs and bristles are 

 slightly longer, than in snbopaca. The color of the pollen over the 

 body is more greenish in millbrcc, yellowish in snbopaca. Occasional 

 specimens with lighter pollen and yellow legs occur in millbrff, the 

 lightest ones corresponding exactly with the other species; just as, 

 among the subopacas of the interior, dark-legged specimens are 

 occasionally seen. In either case 98 per cent, or so are true to type. 

 As I have not studied the larva and puparium of millbrcc, I feel that it 

 would be premature to assert the identity of the two species. 



The puparium as figured and brieHy described by Jones seems to 

 be the same as in snbopaca. His figure and description of the larva 

 indicate a small amount of dorsal pigmentation and a larger develop- 

 ment of the anterior spiracles, but the examination of material in 

 both species would be needed to detennine whether a specific differ- 

 ence exists here. The egg according to Jones is shaped like an apple- 

 seed, and has tufts of minute hairs on its surface ; it is attached by its 

 larger end to floating bits of vegetation or puparia. 



Distribution. 



Jones mentioned portions of San Francisco Bay, from San Mateo 

 to San Bruno. I have collected it in the following localities : 



Salt marshes of S. F. Bay adjacent to Palo Alto, in February, 

 April, August and October. 



Alum Rock park, near San Jose, Cal., 20 miles or so from the 

 bay, April 5. 



Santa Monica, Cal., July 31. 



San Juan Island, Wash., several places, May to July. 



Professor C. F. Baker sent me a specimen collected at Laguna 

 Beach, Southern Cal. ; while I am indebted to Professor Melander for 

 specimens taken May 17 at Olga, on Orcas Island, Wash. 



Habits. 



The species keeps close to the seashore. The Alum Rock record 

 above is the only apparent exception, and there the park with numer- 

 ous mineral springs is traversed by a stream which empties, or at 

 one time did, into San Francisco Bay. 



