6 
Psyche 
[March 
abdomen, ovipositor, cerci; S. pygmaea Meunier for the shape of 
the prothoracic lobes; S. oustaleti Brongniart, specimen 22-3, and S. 
agnita (Meunier) for the five-segmented tarsi and legs; and S. 
laurentiauxi, n.sp., for the beak. It should also be pointed out that 
since the maxillary palpi are incompletely preserved in any specimen 
of Stenodictya , they have been represented in the restoration to the 
length of those in Eugereon hoeckingi Dohrn; the labrum, which is 
indistinct in specimens of Stenodictya , is drawn as it is in various 
species of Palaeodictyoptera belonging to other genera; and the length 
of the ovipositor, also incomplete in specimens of Stenodictya , is 
drawn to its length in Homaloneura ornata Brongniart. 
A dense archedictyon, more or less approaching that of the 
Dictyoneuridae and related families, occasionally occurs within the 
homoiopterid and spilapterid groups of families. In the Homoiop- 
teridae it is very dense, for example in Boltopruv ostia nigra 
(Kukalova, 1958), and it is well developed in Homoioptera 
woodwardi. In the Spilapteridae, the archedictyon is presumably 
completely reduced in all genera and the anastomoses between the 
cross veins are only rarely present, but the cross veins them- 
selves are exceptionally dense. Nevertheless, in the closely related 
family Eubleptidae, there is a dense archedictyon between the 
cross veins. A special case of modified archedictyon occurs in the 
Fouqueidae, particularly in the genus Fouquea. The coarse, ex- 
tremely dense cross venation in that genus recalls very much the 
process which has taken place in some roaches, in which the dense 
reticulation in the more primitive Carboniferous forms became 
restricted into markedly dense patterns in Permian forms. Never- 
theless, among all Palaeodictyoptera, the archedictyon of the 
Dictyoneuridae is certainly the most even and tends least to form 
cross veins. Its presence, together with specialized morphological 
features, is not surprising, this phenomenon being known as mosaic 
evolution. 
Of the genera included in the Dictyoneuridae by Laurentiaux 
( 1 953 ) > Athymodictya Handlirsch is to be referred to the Eu- 
bleptidae, Dictyoneurella Laurentiaux to Archaemegaptilidae, 
Mecynoptera Handlirsch perhaps to Archaemegaptilidae and Bolto- 
pruvostia Pruvost to the Homoiopteridae. 
The following are the basic characteristics of the Dictyoneuridae: 
Fore and hind wings very similar. Main veins without coalescence. 
Sc ending on costal margin beyond midwing; Ri 'extending nearly 
to apex; Rs with several branches; MA unbranched, usually strongly 
