570 Mr. Kenneth J. Morton on 
therefore more typical; unfortunately, it contains no 
males. The third contains larger ¢ examples also from 
Ziirichberg in May ; the wings in these are brownish and 
transparent ; these are most doubtful. 
With regard to distribution, in addition to Switzerland 
and Bohemia, insects which are temporarily referred to 
this species are in Mr. MclLachlan’s collection from 
Carinthia and the Schwarzwald. 
Nemoura lacustris. 
N. lacustris, Hd. Pictet, Névropt. d’Hspagne, 
p. 2h ir). 
Head and pronotum blackish or piceous, antennz concolorous, 
occiput and margins of pronotum sometimes paler. Pronotum 
nearly as broad as head without the eyes, sub-quadrate, lateral 
margins scarcely receding. Legs dingy testaceous, darker at apices 
of joints. Wings greyish, sometimes with a faintly brownish tint, 
subhyaline, iridescent, x nervures faintly clouded, clouding of 
pterostigma often leaving a clear costal space almost as in Meyer ; 
radius slightly upturned at apex. In the ¢ the genitalia are very 
similar to those of marginata, but in none of the examples ex- 
amined are the pectinations of the sheaths flanking the upright 
pieces visible, and the upturned spines are apparently shorter and 
stouter. Exp. al., 19 mm. 
Closely allied to N. marginata, but apparently distinct 
on account of the much shorter and stouter upturned 
spines of the ¢. The examples from which the de- 
scriptive notes are taken are in Mr. Mclhachlan’s 
collection; they came from Portugal and_ the 
Pyrenees. 
There is doubt about the application of Ed. Pictet’s 
name. I have seen the types, and they bear resemblance 
to the insects from which the above description is drawn, 
but they now lack abdomens. 
The group which contains the three species described 
as Meyert, marginata, and lacustris is the least satis- 
factory of all here dealt with; the appendages are 
complicated in the dry insects, and difficult to under- 
stand ; confusion between degrees of exsertion and real 
differences of structure seems to be a danger to be 
specially guarded against. 
