NEUROPTERA— EPHEMERID^. 123 



Lengthof body, 17™"'; breadth of thorax, 4""; of head, l"'"; length of 

 caudal setae, 6°"°. 



P^^pa. — The form is altogether that of the larva, but th§ legs are better 

 preserved, showing them to be as long in this species as in E. immobilis, 

 but to differ in their almost uniform slenderness throughout, the tarsi being 

 scarcely narrower than the femora. The wing pads are distinctly *ntiarked 

 in dark brown and are reniform in shape, of nearly uniform width and 

 nearly three times as long as broad, the basal half of their inner edges 

 meeting at less than a right angle, and the distal halves parallel and ap- 

 proximate along the mediodorsal line, the outer edges gentl}^ concave and 

 the tips well rounded. The stone is broken at the tijj of the body in the 

 only specimen, so that the caudal setae are not preserved. 



Florissant. Five specimens, Nos. 233, 1070, 1516, 10385 (larvae), 

 10660 (pupa). 



5. Ephemera interempta. 



This smallest of the epliemerids from Florissant, represented by a nearly 

 complete pupa and the terminal segments of what may be either larva or 

 pupa, and which appears to belong here, differs considerably in structural 

 features from the others. The former only will be described. 



Pupa. — The body is tolerably stout, largest at the thorax where it 

 tapers forward toward the head, which is fully three-quarters its width. 

 Posteriorly the abdomen remains in its basal half very nearly as broad as 

 the widest part of the thorax, and only tapers i-apidly a little before the tip, 

 which is more rounded than usual and scarcely one-third as broad as the 

 thorax The head is rounded, a little broader than long ; the legs only 

 moderately stout, all the femora subequal and about as long as the head. 

 The wing pads are subtriangular, tapering pretty uniforady to a rather 

 broadly rounded tip about half as broad as tlie base, the inner margin bent 

 close to the base, and the basal portions of the two pads forming an angle 

 much broader than a right angle ; they differ therefore altogether in form 

 from the two species of which nymphs are known. The abdominal joints 

 are more than twice as broad as long and wholly devoid of the markings 

 which distinguish all the other species. The caudal setae are about one- 

 third as long as the abdomen, and unfringed. Only the base of the median 

 seta is preserved in the type, but in the other specimen referred here it is 

 as long as the lateral. 



