12 
Psyche 
[March 
dividing the tergites. The oblique ridge which extends out from 
the posterolateral angles of the segment ends freely on the tergite 
surface and is not connected with the transverse ridge. All struc- 
tures mentioned in all probability served to strengthen the abdominal 
wall. 
Fore wing: length 66 mm, width 17.5 mm. Anterior margin 
convex, posterior margin with a convex curvature at the end of 
MA; apical third of wing very narrow; subcostal area broad, but 
narrowing a short distance beyond the base of the wing. Rs with 
5 simple branches. Anal area with 6 veins, mostly unbranched. 
Cross veins in the subcostal area and the sc-r area dense, regular, 
with but few anastomoses. 
Body structures: Head 1.5 mm long; 7 mm broad. Clypeus very 
large, quadrangular in form and having a median ridge and three 
pairs of transverse ridges, the anterior pair being weakly indicated. 
Prothoracic lobes reaching about 2/3 the width of the fore wing, 
with 7 branched veins. Thoracic segments about equal in length 
and each with a median furrow. Length of mesothorax, 7.8 mm, 
of metathorax 7.2 mm. Prothorax narrower than mesothorax. Abdo- 
men slightly broader than thorax, about 39 mm long. Lateral parts 
of abdominal segments laterally dilated ; posterolateral angles pointed, 
projecting somewhat laterally. First abdominal segment slightly 
narrower than the following ones, the other abdominal segments 
almost equal in size; transverse tergal suture well developed. 
Stenodictya lobata differs from spinosa in having longer thoracic 
segments, a narrower abdomen, less pronounced posterolateral angles 
on the tergites; and a broader forewing, which lacks the pronounced 
convex curve along the hind margin. 
Stenodictya spinosa (Brongniart) 
Figures 53, 54 
Scudderia spinosa Brongniart, 1890: 6, pi. II, fig. 1. 
Stenodictya lobata Brongniart, 1893: pi. 22, fig. 2. 
Brongniart’s attempt to synonymize spinosa with lobata has already 
been noted. The original figure of specimen 22-2 showed some 
significant differences as compared with the type specimen of lobata, 
such as the size of the thoracic segments, the length of legs, the 
shape of the wings and the structure of the abdomen — all of which 
are certainly acceptable as the bases for specific differentiation in 
the Palaeodictyoptera. Sexual dimorphism, of course, can not be 
excluded as an explanation of these differences, spinosa obviously 
