Subfamily CorDULEGASTERINAE 
Large black and yellow dragonflies, with eyes approximated or 
meeting at a single point on the top of the head. Labium with a 
median terminal cleft. Stigma with no brace vein at proximal end. 
Females with a rather crude ovipositor. 
The group is a small one, pertaining to the northern hemisphere and 
there is in our fauna but a single genus. 
24. CORDULEGASTER 
The Biddies 
These are clear-winged stout, hairy, dragonflies, of rather primitive 
aspect. The thorax is blackish, with a pair of oblique pale stripes on the 
front and two additional pairs on the sides. Legs black. Wings hyaline. 
Face mostly greenish or yellowish, but with the clypeus always fuscous. 
The occiput and the abdominal markings are very different in the 
different species. All the species frequent clear-flowing woodland 
streams, where their nymphs dwell in the bottom ooze of the settling 
basins. 
In terms of the stripings of the Gomphus thorax (fig. 30) the stripes 
of the 1st pair have fused to form a middorsal triangular spot, those of 
the 2nd and 3rd pairs have fused completely (except for a little rift in 
C. diastatops). Those of the 4th and 5th have likewise fused and a 6th 
has developed behind, and all have become conjoined longitudinally 
by their ends. 
Nymphs of this genus agree in the following points: the body is 
stout, rough hairy, cylindric, tapering beyond the middle of the abdo- 
men to a pointed apex, the longitudinal axis upcurved at both ends, the 
tips of the eyes and the abdominal appendages being the highest points. 
The antennae are seven-jointed, slender. The eyes cap the angular 
antero lateral prominence of the head and extend a pair of sharp points 
internally on the vertex from their hind angles. Hind angles of the head 
rounded, the hind margin not obviously concave posteriorly. The 
labium is very large, extending posteriorly between the bases of the 
middle legs, its dilated, spoon-shaped anterior end covering the face up 
to the antennae, and meeting above a convex frontal prominence, whose 
margin is fringed with sensory hairs. The mentum is triangularly 
widened beyond the middle; its median lobe is produced in a median 
tooth which is bifid on the median line; its lateral lobes are broad, 
152 
