GOMPHUS 111 
corners. Thoracic stripes of the first pair narrow above and widened below to a 
confluence with stripe 2 above the collar, leaving only an isolated oblong stripe 
of yellow between. Stripes 2 and 3 confluent above and below, and separated in 
the middle by a narrow line of yellow. Stripe 2 is broader than 3. Stripes 4 and 5 
are complete, and the area between is washed with pale brown. Wings hyaline, 
with brown veins and tawny stigma. Legs brown, paler basally to the middle 
of the femora. Tibiae brown externally. The middorsal line of pale triangles 
on the abdomen is slender, abbreviated on segments 6 and 7, widened and further 
abbreviated on 8; 9 and 10 brown above. The side margins of the very moderately 
dilated segments 7, 8 and 9 are broadly washed with obscure yellow. Appendages 
brown. 
64. Gomphus quadricolor Walsh 
Walsh ’62, p. 394: Mtk. Cat. p. 96. 
Length 44 mm. Expanse 54 mm. Mass., Wis. to Tenn. 
A small green species striped with blackish brown, and with blackish ab- 
domen. Face and occiput greenish. Rear of eyes black, with a mid-lateral pale 
spot. Thoracic stripes of the first pair fused except in the middle of the carina, 
and parallel sided, each not as wide as the bordering greenish stripe, truncate 
below at the collar, but narrowly conjoined with the brown collar band on the 
median line. Stripe 2 reaches the brown of the crest by a narrow prolongation, 
fuses with stripe 3, isolating a triangular greenish spot above, then separates 
from 3, leaving a green stripe below. Stripe 3 is broadest at the point of fusion 
with 2, and tapers downward therefrom. Stripes 4 and 5 are complete, narrow, 
and conjoined at the upper end. Wings hyaline; veins black. Legs black. The 
usual middorsal pale stripe of the abdomen is reduced to basal triangles on the 
middle segments. Segments 8, 9 and 10 are wholly black above and yellow at 
side margins. Appendages black. 
Subgenus ARIGOMPHUS 
These are graceful and strong flying Gomphines of less distinct color- 
ation than the preceeding, the dark stripes of the thorax and the pale 
spots of the abdomen becoming diffuse or obsolete. The hind femora of 
the male are hairy, and of the female are spiny beneath. The apical 
margin of the eighth abdominal segment is cut obliquely, being longest 
on the dorsal side. The posterior genital hamules of the male slope 
backward. 
The nymphs of this group are lanceolate in outline, the wide abdomen 
being narrowed before the end and then drawn out in a long tapering 
point so that the side margins of the long ninth segment are concave. 
The tibiae have strong burrowing hooks. The mentum of the labium 
has parallel sides and a convex median lobe that usually bears one or 
more teeth in the middle of the front border. The lateral lobes are 
blunt at the tip and bear, within, a series of jagged and widely spaced 
teeth that diminish in size proximally. Dorsal hooks are wanting except 
