18 
Psyche 
[Vol. 90 
branches, originating from R in basal third of the wing; CUP 
simple, originating from very base of R, connecting to RS by a short 
cross vein; M four-branched, fusing for approximately 9 mm at its 
base with CUA; CUA also four-branched; CUP simple, arising 
independently of CUA at the wing base. CUP elbows towards CUA, 
connecting to it by short cross vein. Anal veins slender and 
bifurcating. Well-developed reticulation present in anal area. 
Hind wing: length 40-48 mm, width 14-16 mm; SC and R same 
as in fore wing; RS pectinate with five branches, arising from R near 
wing base; M arising from near base of RS and deeply cleft with two 
or more terminal bifurcations; CUA and CUP parallel and 
independent at wing base. Anal area not well preserved, only 
slightly expanded, and with reticulated venation. 
Prothorax: distinctly large and swollen posteriorly. There are 
nine prominent spines symmetrically arranged in the swollen region 
(see fig. 8). Width at widest point 10-13 mm, length 20-22 mm; 
spines 7-10 mm in length. One, possibly two, vertical spines extend 
from the anterior of prothorax, posterior to head. 
Body: large, ranging from 70 mm to 75 mm (tip of wing to 
anterior tip of prothorax). Legs long and thin. 
Diagnosis 
This species may be distinguished from the other species in the 
genus by the large prothorax and well-developed spines (longer in 
this species than in any other); and the overall body size which is 
distinctly larger than that of either G. vetus or G. collaris from 
Mazon Creek. Although venational characters do vary intraspecifi- 
cally, it should be noted that in the fore wing M connects to RS by a 
small cross vein, and that the anterior branch of CUP connects to 
CUA also by a small cross vein. This contrasts with the other species 
in the genus in which one finds an actual anastomosis of these veins. 
Geological range: Westphalian D. Occurrence: Mazon Creek, 
Illinois, U.S.A. 
Holotype: USNM 35574. Specimen examined. Reverse half 
only.^ The bulbous region and spines of the prothorax are well 
preserved in this specimen. Only the costal margins of the fore wings 
are present, but venation of the hind wings is clear, except in the 
anal area. All evidence of the head and anterior region of the pro- 
thorax has been lost. 
'<The obverse half was originally in the Daniels collection, the location of which is 
not known (see Carpenter, 1965, for further details on this collection). 
