June, 1912.] AlDRICH : BlOLOGY OF WESTERN EpHYDRA. 81 



during the pupal period, are here but little if at all turned forward, and do 

 not seem to serv^e an important function in this species. Behind the last 

 prolegs the base of the anal tube looks like another body segment, those 

 preceding it being about as slender as it is ; the continuation of the tube is 

 not strongly chitinized, but thin-walled and pale in color. The diverging 

 terminal tubes each contain a trachea, which continue separate down into the 

 body; the pair of filaments at base of tube do not seem to have tracheae, at 

 least they have no vestiges of spiracles at the apices as the terminal branches 

 obviously have. At the front end of the puparium, there is a flattened space 

 above, well defined, extending to hind edge of the segment bearing the first 

 prolegs — only a short space, as the anterior segments become very small as 

 the puparium forms; this plate cracks from the front end backward along 

 each side, and sometimes allows the escape of the fly without the breaking 

 off of the entire anterior end of the puparium, as is supposed to be the case 

 in the group Cyclorhapha, to which Ephydridae belong. 



Pupa. — Upon removing the puparium, the enclosed pupa is readily ob- 

 tainable. It is white in color and shows the outlines of the members of the 

 future fly. The large proboscis is flattened down upon the prosternum ; on 

 each side of it the three legs are closely placed in regular order, and the 

 wing follows the last leg ; most of the dorsum of the thorax and abdomen is 

 exposed, the wings being bent down along the side and of small size. It is 

 difficult to make out many important features in the pupa, there being still 

 one covering membrane over the future adult, and the tissues of the latter 

 being still in an unfinished condition. The appearance is like the pupa of 

 E. hians, in the half-tone. Fig. 15. 



Habits. 



Distribution. — The in.sect is abundant in all parts of Great Salt 

 Lake. It was reported to me by Mr. D. W. Coquillett as being rep- 

 resented in the United States National Museum from Salton Sea, 

 Cal., and Tucson, Ariz. The material to which Jones gave the name 

 of E. cinerea came from Southern California, without designation of 

 locality. Recently a single specimen has been sent me by Professor 

 C. F. Baker which was collected at Laguna Beach, Cal., which is on 

 the Pacific Ocean. I have not learned the exact habitat of the insect 

 in this case, but I presume it was found adjacent to some salt waters 

 back from the sea-beach ; it would be surprising to find it passing its 

 lasral stages in actual seawater. 



My observations on the habits of the species were all made at 

 Great Salt Lake, in the last of July. 1908, and the early part of 

 July, 1911. 



Egg and Early Larval Stages. — Of these I know nothing from 



