90 Bulletin Wisconsin Natural History Society. [Vol. 6, Nos. 1 — 2. 
Gomphus ventricosus Walsh. This species is very similar to 
vastus in color and markings. The chief specific difference is the en- 
tirely yellow or olive face. A minor distinction is that the black 
humeral and antehmneral are connected for some distance. The vul- 
var lamina of the female are bifid, the apices acute, more diverging- 
than vastus. The life zone is the Upper Austral. 
Gomphus amnicoia Walsh. Colors j-ellow and black. Face with 
narrow black lines on the sutures, thorax black, marked with yellow: 
mesothoracic half -collar, two short oblique bars on the dorsum, a nar- 
row, interrupted antehumeral, and nearly all of the sides, yellow. A 
broken line is found on the first lateral suture. Legs black, anterior 
femora beneath and hind femora with the exterior surface greenish 
yellow. Abdomen with a dorsal line on 1 — 2 yellow. A spot on 3 and 
8, sides of 1 — 2 and 8 — 10 yellow. The vulvar lamina are contiguous 
at the apex. The species resembles uotatus, from which it difllers by 
its brighter color, the less complete thoracic markings, and the less 
divaricate male appendages. The vulvar lamina of notatus are short, 
the lobes separating, the apices rounded, conical. Life Zone : Upper 
Austral. 
Gomphus scudderi Selys. Black, brown and greenish yellow. Face 
banded with black, thorax fuscous, marked with greenish yollow. Mid- 
thoracical and antehumeral stripes narrow. Abdomen black, segments 
7 — 9 greatly dilated. Yellow basal rings on 3 — 10, the rings reduced 
on the posterior segments. Dorsum of 1 and 2 with a stripe of greenish 
yellow, 2 with a lateral spot. Faint yellow spots on sides of 4 — 6, 
prominent basal spots on 7 — 9. Dorsum of 8 and 9 with a small basal 
yellow spot. SegTQcnt 10, except for the linear basal ring, and the ap- 
pendages black. Life Zone : Boreal. 
Gomphus vastus Walsh. Face heavily banded with black. Thorax 
black, the markings greenish j^ellow. Dorsal stripes oblique, con- 
nected with the antehumeral above and the mesothoracic half-collar 
below, j^ellowish green. Abdomen black; segment 1 — 2 pale green; 
dorsum" of 3 — 7 with an interrupted band of greenish yellow, ending 
in a triangular on the base of 7. Sides of 8 with a basal spot, and 9 
largely bright yellow. Superior appendages black. Legs black, the 
anterior femora green beneath. The vulvar lamina of the female are 
more than half the length of 9, bifid at the apical third, the apices 
acute, the tips approaching each other. 
Suhgenus 8TTLURUS. In a disquisition on this subgenus Mr. Wil- 
liamson has included five species in this group. Of these, however, Dr. 
Needham has diverted two, amnicoia and scuclcleri, to the group Gomph- 
urus, leaving plagiatus, spiniceps, and notatus to represent the group. 
Styhirns differs from Gomphurus mainly hy the long, cylindrical (not 
• dilated) abdome*n, and the anterior direction of the posterior male 
genital hamule. The three species differ, as follows : 
1. Abdomen black, marked with yellow or green 2 
Abdomen j^ellowish brown, marked with yellow or green ; seg- 
ment 9 much shorter than 7 plagiatus 
2. Face with distinct black bands ; segment 9 shorter than 7. . .notatus 
Face suffused with black, no distinct markings ; segment 7 and 
9 about equal in length spiniceps 
