1947] 
Banks — Characters in the Perlidce 
283 
it at an angle or a curve ; and further as in the above 
table. This is closely similar to the condition in Allo- 
perla. 
Nanoperla gen. nov. 
Type : Chloroperla minuta Bks. 
This was placed in Isoperla by Needham and Claassen 
and by Frison. It differs from Isoperla by the more 
widely separated posterior ocelli, fully twice as far apart 
as each from eye ; by the lack of an angle at anterior cor- 
ners of the pronotum; in the hind wing the median cell 
is fully twice as long as its pedicel ; the legs and setae are 
shorter; the medius of fore wing is often stopped by the 
first median cross-vein, and does not extend basally close 
to the radius as is common in Perlidae, this is similar to 
Hastaperla and Chloroperla; in the anal area the third 
anal vein usually branches from the second at the end of 
anal cell, sometimes a little beyond, rarely before it. Its 
dark fore wings with the costal area yellowish also sepa- 
rates it from Isoperla. In both sexes the genitalia are 
different from the normal Isoperla. 
Nanoperla minuta occurs in the mid-western States, 
Ohio, Michigan, Illinois. It may be, as Frison suggests, 
that it is the Chloroperla nana Walsh. His description 
is short, and the size is a little large for a dried specimen ; 
his unique type was from Rock Island, Illinois ; Frison 
says that minuta occurs in the central and eastern part 
of Illinois. 
Walshiola gen. nov. 
Type : Perlinella signata Bks. 
In Isoperlinae, the upper branch of cubitus continues 
the line of the base; cubito-anal at tip of anal cell or a 
little beyond; radial sector forked once or twice ; the head 
back of eyes at once curves inward ; median groove 
usually reaches the occipital line, which, beyond each 
ocellus fades; hind ocelli looking out laterally over a 
broad, shallow groove; ocellar triangle a little broader 
than long; a rather wide space between arms of the 
V-mark; fourth antennal joint about or fully as long as 
broad; palpi long and slender, fourth joint rather longer 
than third. 
