90 THOMAS SAY FOUNDATION 
lateral angle of the head; hind ocelli almost twice as close to each 
other as to the eyes; a wavy occipital ridge present. Antennae 
yellowish with about seventy-five short segments. 
Pronotum a little less than three times as wide as long; front 
margin nearly straight or slightly convex; hind margin rather 
deeply concave in center; sides and angles broadly rounded, the 
former produced into wide flanges. Meso- and metanotum similar 
to the pronotum in color and markings; sides of wing pads broad- 
ly rounded and bearing on the lateral margin a series of spinulose 
hairs; legs flattened; femora and tibiae with a thick fringe of 
white hairs. 
Abdomen flattened, posterior margin of each segment with 
a row of stout hairs; cerei very long, and tapering from a rather 
stout base to a very slender apex; composed of about fifty-five 
segments, the basal segments very short, apical ones long and 
slender, each segment terminating in a whorl of short spines; 
inner margin of cerei with a fringe of hairs. 
Nine pairs of branched, filamentous gills as follows; two pairs 
on each of the outer bases of the pro- and mesothoracie legs; one 
pair at the outer base of the metathoracic legs; one pair at the 
lateral conjunctivae between the pro- and mesothorax; one pair 
between the meso- and metathorax; and two pairs on the meta- 
thorax. Each of these nine pairs of gills is much branched, and 
extends outward beyond the margin of the pro-, meso-, and meta- 
notum; anal gills absent. 
Fairport, Iowa. 
Acroneuria theodcra Needham and Claassen 
(Plate 26, fig. 206.) 
Length of body up to 34 mm.; antennae up to 14 mm.; cerci 
up to 19 mm. 
The nymphs of this species are easily confused with the nymphs 
of A. californica because of their close general resemblance. In 
A. theodora however the ocellar triangle is completely covered 
with brown except for a small round yellow spot in the center 
of the triangle in some of the nymphs, while in A. californica the 
hind ocelli are always surrounded by a transverse yellow spot. 
In A. califormca the femora are uniformly yellowish, while in A. 
theodora the middle portion of the femora is darker than the 
rest. A. theodora is also larger than califormea. 
General color yellow and brown, the entire body covered with 
short brown hairs. 
