32 
Psyche 
[March 
Ephemerella rotunda Morgan 
Male adult: (reared from nymphs collected in Cascadilla 
Creek, Salmon Creek, Otter Creek, Van Buskirk’s Glen, 
North Harford Brook, North Spencer Stream and Fall 
Creek) . 
Measurements : Body 9 mm., tails 12 mm., foreleg 9 mm., 
fore wing 10 mm. Head light brown; compound eyes orange- 
brown. Thorax and abdomen a shiny medium brown. Legs 
yellowish or tan. Tails ringed with dark brown at the base 
of each segment. Axillary cords of the fore wing prolonged 
into slender spines projecting posteriorly on either side of 
the hinder lobe of the mesothorax. Wings hyaline. Penes 
with stout spines. 
Subimago: Wings subhyaline. 
Nymph : (dark variety) . 
(Taken in Cascadilla Creek, Otter Creek, Salmon Creek.) 
Measurements : body 9-10 mm ; tails 6 mm. Head smooth 
and round; labium grayish in color. Thorax broad and 
flaring, the wing pads descending well over the first several 
abdominal segments ; frontal angles of the prothorax with 
a prominent tooth, lateral margins with a broad thin shelf- 
like edge ; front angles of the mesothorax with a prominent 
triangular tooth. Posterior angles of the head forming al- 
most right angles. General color of abdomen blackish- 
brown, segments 5, 6 and 7 yellowish in color. Dorsal spines 
very well developed, occurring on segments 2-9. Lateral 
margins of segments 3-9 acuminate and slightly incurving, 
acuminate but not incurving on 10. Legs short and stubby 
relative to body; yellowish in color, the tibia and tarsus 
with dark brown bands. Gills present on abdominal seg- 
ments 3-7, the 7th gill almost completely covered by the 
6th. Tails lightish with several slightly darker bands, and 
with circlets of stiff hairs at the bases of the segments; 
fringed with longer hairs for the last two-thirds of their 
length. These longer hairs gradually diminish in length 
