ERPETOGOMPHUS. 
Females. 
A. Occiput with a posterior tubercle on each side, its hind margin concave ; 
lobes of the vulvar lamina in contact, each lobe rounded at tip and 
reaching to one-fourth the length of abdominal segment 9; tibiee supe- 
riorly black ; abdomen 35°5-37'5, hind wing 32°5-34°5 mm. 
AA, Occiput with no posterior tubercles. 
B. Hind margin of occiput almost straight or occasionally bilobed, dark 
submedian thoracic stripes absent. 
C. Tibi superiorly yellow or with yellow lines, hind margin of the 
occiput with a median notch, no dark stripes on the thorax ; 
abdomen 33-87, hind wing 29-35 mm. , oe ee es 
CC. Tibiz superiorly black, no median noteh i in the hind margin of the 
occiput, dark brown antehumeral and humeral stripes present, the 
former reaching to the mesinfraepisternum ; abdomen 35-37, hind 
wing 31-32 mm. woe ee : a 
BB. Hind margin of occiput concave, or trilobed with the median lobe 
lower than the lateral lobes; tibiz black superiorly. 
D. Lobes of the vulvar lamina separated by an almost quadrangular or 
U-shaped interval three to four times as wide as the width of either 
lobe ; abdomen 31-35, hind wing 27-32 mm. . . 
DD. Lobes of the vulvar lamina separated by a triangular or semi- 
circular interval half as wide to as wide as the width of either lobe 
at its base. 
E. First and second lateral * thoracic sutures without dark stripes ; 
dorsal yellow on the middle of abdominal segments 3-6 of nearly 
equal width, or elliptical. 
F, Dark antehumeral and humeral stripes united superiorly, no 
traces of submedian thoracic dark stripes; abdomen 35-37, 
hind wing 31-32 mm. . a woe 
FF. Dark antehumeral and humeral stripes not united above, sub- 
median dorsal thoracic stripes (or traces of them) present ; 
abdomen 31:5-35, hind wing 28-80 mm. . oo. 
EE. First and second lateral thoracic sutures each with a well- 
developed dark stripe; dorsal yellow on 3-6 much wider at 
half than at one-fourth the length of the segment, forming a 
lozenge-shaped spot on the middle ; abdomen 34-838, hind wing 
30-35 mm. 
161 
5. cophias. 
6. crotalinus. 
8. sipedon, form a. 
3. elaps. 
8. sipedon, form 6. 
2. viperinus. 
[9. compositus. | 
* Jt should be observed that my usage of these terms does not correspond with that of Prof. Needham. 
What I, following de Selys (Monogr. Calopt. p. 11 ; Monogr. Gomph. p. 29) and Rambur (Neévr. p. 8), have 
called the humeral, first lateral and second lateral sutures (Trans, Amer. Ent. Soc. xx. pp. 159-160, t. 2. 
fig. 13) are termed by Prof. Needham “ first (humeral), second and third latural sutures” respectively 
(Bull. 47, N. Y. State Mus. p. 434, fig. 10 B). 
BIOL. CENTR.-AMER., Neuropt., June 1905. 
y 
