8 
Psyche 
[March 
to work out the venation satisfactorily and to add descriptions of 
these specimens to the account included here. 
Since the venation of the Dictyoneuridae is very simplified, as 
well as homogenous but individually variable, it does not offer much 
basis for taxonomy. The relative positions of the Rs origin and the 
M division into MA and MP, used as specific and even generic 
characters by many authors, may vary even within one individual 
specimen’s fore and hind wings (see for example Stenodictya lau- 
rentiauxi sp. nov.). Also, the number of branches can only be 
used to a limited extent, as additional twigs are frequently formed 
by the archedictyon, elements of which may or may not reach the 
posterior margin. Having rich material for comparison at my dis- 
posal, I find that the general outline of the wings, especially the 
degree of undulation of the posterior margin and the detailed 
structure of the archedictyon (shape and size of cells, areas occupied 
by cross veins, presence of twigs) are the same in fore and hind 
wings and are therefore additional and useful taxonomic characters. 
In view of the situation noted above, I believe it is not advisable 
to form new genera in this family unless they are completely obvious 
and necessary, since such taxa just cannot be satisfactorily sub- 
stantiated. I have not been able to study Dictyoneuridae in deposits 
other than that of Commentry but it seems very probable that the 
total number of genera will diminish after revisional studies . 4 
The wings of the Dictyoneuridae are about equal in length or 
the hind pair may be a little shorter; they are similar in venation 
and in the undulation of the posterior margin. Fore wing with the 
anterior margin strongly curved near the base. Precostal strip 
pronounced; postcostal veins simple, arising from the very base of 
C, ending on Sc or forming a fork towards C and Sc. Sc terminating 
beyond midwing. Rs pectinate, originating at about mid-wing; 
MA, MP, CuA, CuP usually simple and parallel, sometimes with 
additional twigs formed by the archedictyon. Anal area relatively 
broad, with about five anal veins, sometimes forked. Archedictyon 
irregular, occasionally producing twigs. In the costal, sc-r and 
proximal part of r-m areas there are dense, regular cross veins, 
4 In the collections of the Institut, I was not able to find the type specimen 
of S. vasseuri Meunier, 1914. Since the specimen was not present in the 
collection in 1938 (pers. comm., F. M. Carpenter) and since no photograph 
of it exists, I have not included this species in my present account. S. 
minima Brongniart, 1893, is based on a very fragmentary specimen and 
since it shows no other characteristic than the small size, I am referring 
this species to Dictyoneuridae inc. gen. 
