562 Mr. Kenneth J. Morton on 
considerably turned up just where it joins the outer margin ; the 
4th apical cellule is biangulate at the base ; and in the hindwings 
there are several transverse nervures in the intercubital areas, a 
state of things not normal in other species. In the ¢ the median 
prolongation of the ventral plate and the lobe on this plate are 
both moderate ; the lateral appendages are slender, slightly curved, 
and narrowing towards the apex, which terminates in two hooks, 
the lower of which is most evident ; seen from above or beneath, 
these appendages are straight, the apex slightly out-turned with 
the tip of the hook turned inwards. In the 9 the apex of the 
abdomen has two large ovate lobes and a pair of longer simple 
appendages. Exp., g, 12} to 20mm.; 92, 15 to 24 mm. 
This species is common in Britain, and probably over 
the whole Palearctic region. I have seen it from Arctic 
Norway, Finland, the Vosges, Schwarzwald, Switzerland, 
Bohemia, Portugal, and Sarepta; it is also mentioned by 
McLachlan in ‘‘ Nedchenko’s Travels,”? as seen by him 
from Turkestan. ‘To what altitude it goes is uncertain; ~ 
very small examples are in McLachlan’s collection from 
the Col du Lauteret, Alps of Dauphiné. It seems 
attached to standing waters, and even occurs in places 
where there is little or no surface-water in the dry 
seascn. ‘Ihe time of appearance varies with locality 
from April to August, and probably later. 
At once one of the largest (but varying greatly in this 
respect, some minute examples occasionally appearing) 
and best-defined species of the whole genus. The granu- 
lose prothorax, the condition of the neuration, and the 
appendages of the ¢ are all characters which can be 
relied upon. For this reason it is the one Nemoura 
regarding whose name there is something like unanimity 
of opinion at the present time. Rambur’s description 
of lunata is good; he refers to the appendages of the ¢. 
The eight species of Stephens’ above narrated are cer- 
tainly all to be referred bere according to the types in 
British Museum ; pusilla is a small ¢. 
Nemoura avicularis, n. sp. 
Head and pronotum shining black, the latter sometimes very 
narrowly outlined in yellow or orange. Meso- and meta-nota also 
shining black with a brown posterior marking. Pronotum very 
slightly broader than the head without the eyes, foremargin and 
sides hardly rounded, borders not distinct in the dry insect, disc 
