1863.] 
177 
It remains to compare this 9 imago from Rock Island with P. hili- 
neata Say, Walsh {limbata Hagen.)— 9 Imago from Chicago, expanse 
44 mill. Seta 30 mill.; Ant. leg II mill.; abdomen in bad condi¬ 
tion.— 9 Imago from St. Louis in alcohol has the dimensions given in 
the Synopsis. [Length 29 mill. Kxp. 46 mill. Seta 20 mill.]—On 
comparing the 9 from Rock Island with these two, it seems to differ 
in its larger size, in its general color being yellow^ very like that of 9 
Hmhata Walsh {hlUneata Hagen,) in its hind wings being without 
bands, and in the color of the feet and of the setae. [^See note 18.] 
P. FLAVESCENS Walsh, % 9 imago. New to me. A good species. 
Easy to separate from similar Baetis by the relative proportions of the 
basal joints Joint 1 is shorter than 2 ; 2=3; 4=1. 
P. INTERPUNCTATA Say, Walsh. P. PULCHELLA Walsh, and P. 
TERMINATA Walsh, I have not yet found time to examine. It seems 
to me that the S % from Maryland, referred to in the Synopsis under 
Bsetis vert Ids Say, are P. j)uleliella^ and the % % from Washington P. 
terminuta. \_See note 19.] 
Ephemera. 
E. NATATA Walk. Cat. I now possess 'S 9 imago and subimago 
from Saskatchawan. 
E. DECORA Hagen, differs in reality from E. decora Hagen, Walsh, 
by the characters mentioned, and is rather yellow than luteous. The 
9 described by me is exactly like the 'S and is from Chicago, the 
habitat of Mr. Walsh’s species. It is possible his species may be E. 
simulans Walker Cat., but the dimensions are a little too small and 
rather those of E. hehes. 
E. NOV. SPEC. I have received from New York 9 imago of a new 
species. It is very large, (length 19‘mill. Exp. 42 mill.) the wings 
hyaline and much spotted, the abdomen very bright yellow immacu¬ 
late. It resembles somewhat E. danica of Europe. 
E. PUDICA Hagen, is probably no Ephemera but a Baetis. Joints 
1—3 of the tarsi in all the feet are long and equal, 4 a little shorter, 
5 equal. I am vexed that I did not entirely omit this solitary speci¬ 
men of a 9 subimago with the head and the tip of the abdomen both 
gone. 
