OX GOMPHUS CORNUTUS TOUGH (0 DON AT A) 
By R. A. Muttkowski and A. D. Whedon 
The present paper is an attempt at a complete summary of 
our knowledge of this interesting Gomphine dragonfly. The 
species was first described by Tough (1900) from two males. 
Until now the*female and the larval stages have been unknown: 
this paper includes a description of both. 
THE FEMALE 
Color olive green, black, and. yellow. 
Face olive green, tinged with yellow, occiput yellow, vertex black. No 
black bands across the face. Occiput yellow, standing back as high as the 
vertex is long (measured axially), circular, with a median notch. Vertex 
black, three brown ocelli. The armature of the vertex is the most remark- 
able feature: On each side is found a spine or “horn” extending obliquely 
upward and backward and giving the animal an “antelopian” or “goat- 
like” appearance (figs. 1 and 2, A, B.). The brown ocellus at the base of 
each horn serves only to heighten this impression. Minnesota specimen 
with a protuberance on the anterior side of each “horn.” 
Thorax olive yellow, with brown or black stripes of the usual Gomphine 
type, though somewhat variable. The mid-thoracic stripes each side of 
the carina may be faint or absent. The lateral sutures of the thorax may 
have brown or black stripes or be without them. Legs with all femora 
yellow beneath, often yellow on the sides of the femora (in the male only 
the front femora yellow beneath). 
Abdomen with hastate spots on each segment, finely interrupted api- 
cally on segment one to segment seven inclusive. Eight with a small 
hastate basal spot, which may be barely indicated, nine black, ten with 
a median spot of yellow. Sides below with yellow spots on the basal two- 
thirds of each segment. 
Appendages half the length of ten, in form like elongate triangles, yellow. 
Vulvar scale (fig. 2, F) two-fifths the length of the sternum of nine, half 
as wide as the segment, the sides making the arc of an elipse, a median 
cleft half the length of the appendage. 
Measurements: Minnesota specimen: f.w., 37 mm.; h.w., 36 mm.; ab- 
domen, 40 mm.; width of head, 7.5 mm. Wisconsin specimen, f.w., 38.5 
mm.; h.w., 37 mm.; abdomen, 44 mm.; width of head 8.5 mm. 
88 
