2 
Psyche 
[March 
Type Genus: Dictyoneura Goldenberg, 1854. 
Brongniart originally conceived of this family as characterized by 
the presence of a dense archedictyon and a specialized venation in 
which there were few branches. Marked attention was given to this 
family in later years and it played an important role in hypotheses 
on insect phylogeny. Brongniart’s original and apparently correct 
conclusion on the specialized nature of the venation in this family 
was rejected or modified by subseqent investigators. Handlirsch, who 
considered the morphology of Stenodictya as supporting his theory 
of trilobite ancestry of insects [by having the prothoraeic lobes and 
abdominal expansions derived from the trilobite cephalon and pleura 
(1908, p. 1304)], believed the Dictyoneuridae to be the most primi- 
tive of all Pterygota. He also thought the order Palaeodictyoptera 
was ancestral to all other insect orders. This latter view was rejected 
by Martynov (1925, 1938), who did, however, follow Handlirsch 
( 1 938, p. 19, 21) in his conviction that the Dictyoneuridae were 
the most primitive of the Palaeodictyoptera. Martynov based his 
conclusions on the presence of four features in the family: a uniform 
archedictyon, well developed prothoraeic lobes, paranotal expansions 
along the abdomen, and a primitive venational pattern, the veins 
having few branches. 
In the light of information acquired in recent years, the arche- 
dictyon seems to be only one of these traits that can be considered 
as primitive. In the geological record of insects, the archedictyon 
appears repeatedly in the more ancient forms of primitive groups, 
becoming irregular or reduced to cross veins in more advanced forms 
(e.g., Paleozoic Blattodea, Protorthoptera, etc.). On the other 
hand, the prothoraeic lobes of Stenodictya and of other Dictyoneuri- 
dae, as far as known, do not differ from those of other Palaeo- 
dictyoptera and cannot be considered as being more primitive. 
Previous interpretations of the so-called expansions of the abdomen 
in Stenodictya seem to be very questionable, after careful study of 
the type specimens concerned. Incorrectly figured by Brongniart, 
who considered them to be homologous to the tracheal gills of mayfly 
nymphs, the expansions seemed to Handlirsch and Martynov as 
evidence for their respective hypotheses on insect evolution. Pland- 
lirsch assumed that the paranotal expansions of the abdomen of 
insects were derived from the pleura of trilobites because of the 
presence of an “oblique furrow.” In his hypothesis on the origin of 
the Pterygota, Martynov assumed that wings of insects arose from 
the paranotal expansions which developed in hypothetical ancestral 
