198 Transactions. 
species taken by myself in the North Island, and by Mr. Howes and 
myself in the Arthur’s Pass district of the South Island. To save the space 
required for a full historical réswmé, full references are given under each 
genus and species to all previously published descriptions and accounts 
of New Zealand stone-flies. 
Before giving keys to the families and genera, or entering upon the 
descriptions of species, it will be necessary to explain the terminology used 
or the wing-venation. This is the Comstock-Needham system, the notation 
of which is given in full in ;he legend of fig. 1. Besides the veins, there 
are also the cross-veins and the separate areas of the wing to be considered, 
neither of which are notated in the figures. For cross-veins the rule is to 
name them from the main veins which they connect. In the Perlaria the 
most important sets of cross-veins are the following :— 
(1.) The medio-cubitals, a series of long cross-veins connecting the main 
stem of M with Cu, below it. The series begins with M,, which was 
originally (as shown by many fossil forms) a true branch of M, and ends 
with the last long cross-vein before or at the forking of M. Whether this 
series is complete or incomplete is a character of generic and sometimes 
of family importance. 
of the main veins, at about the middle of the wing, so as to form a COn- 
tinuous line crossing the wing obliquely from R to Cu,. 
Besides the above there аге two important sets of veinlets—i.e., short — 
branches of main veins resembling cross-veins, but, unlike them, preceded " 
in the larval wing by tracheae. These are— 
"he costal series of veinlets, a short set of anterior branches of vein — 
Se, running across the costal space. One of these, situated not far from 
the base, persists throughout the order in all forms in which the complete — 
P 
set has been lost. This is called the humeral veinlet (hm 
