316 
Isoperla transmarina (Newman) 
Chloroperla transmarina Newman (1838), 
p. 499). Original description, @. 
Isoperla ventralis Banks (1908), p. 66). 
Original description, 6, @. New synonymy. 
Isoperla transmarina was synonymized 
by Hagen in 1861 as the same as bilineata 
(Say), but Ricker (1938) has clearly 
shown that it is not bilineata. Ricker’s 
drawings of the color pattern of the head 
and of the subgenital plate are so charac- 
teristic of ventralis that I have no hesi- 
tancy in placing ventralis as a synonym of 
transmarina. 
Newman’s original description is not 
clear as to sexes involved, but according 
to Ricker the typic specimen now in the 
British Museum is a female. ‘“Inhabits 
Canada, etc.” and “Trenton Falls” indi- 
cate in the original description the source 
of the typic specimen, and the specimen 
considered as the type by Ricker is from 
“an 
Fig. 90.—Nymph of Iso perla transmarina, 
Ittrnois NATURAL History SURVEY BULLETIN 
Vol. 22, Arte 
“North America.” “The statements re- 
varding locality of typic specimen fit the 
general northeastern range of the species 
described by Banks (19084) as ventralis 
and now synonymized as transmarina. 
Tsoperla ventralis was described from 
specimens collected at “Grand Lake, New- 
foundland,” and the typic series is now in 
the collection of the Museum of Compara- 
tive Zoology (No. 11,333). In the orig- 
inal description, reference is made to both 
males and females, but the typic series 
NYMPHAL 
MAXILLA 
NymeHAL LABIUM 
Fig. 91.—Isoperla transmarina. 
now contains only males. Evidently a 
similar situation existed when Claassen 
studied the types, because Needham & 
Claassen (1925) omit any reference to the 
female. 
Through the kindness of Dr. Nathan 
Banks, I was permitted to relax one of 
the typic males and study it closely in com- 
parison with reared specimens. It seems 
advisable to designate this particular speci- 
men as the lectotype and I so do. 
The rearing of adult males and females 
has enabled me to associate conclusively 
the heretofore undescribed nymph of this 
species, and the description of the nymph 
is therefore presented. 
Nympu.—General color yellowish with 
darker areas forming a conspicuous pat- 
tern on dorsum of head, thorax and ab= 
domen, fig. 90. Antennae, legs and anal 
cerci mostly yellowish. 
Head with three ocelli forming an al- 
most equilateral triangle, lateral ocelli 
about as far apart as each is distant from 
inner edge of compound eye; no occipital 
ridge; basal segments of mouthparts not 
extending out from sides of head. Labium 
and maxillae as in fig. 91. 
Pronotum much broader than long with 
