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Bulletin Wisconsin Natural History Society [Vol. 13, No. 2 
Legs long, not heavy, hairy, and with short tibial hooks on the first 
two pairs, the hind femora reaching to or a little beyond the apices of 
the wing pads. 
Abdomen lanceolate, fully rounded dorsally but flattened ventrally; 
widest at the 5th segment from w r hich it tapers evenly to the 1st and the 
Sth, 9th longer and but little graduated, the 10th cylindrical and a trifle 
shorter than the quite uniform main segments; abdominal tip upturned; 
terminal appendages about two-thirds the length of 10th segment, stout 
and conical, the inferior a little the longest. Well marked scars on seg- 
ments 2 to 8, 9th slightly marked. No median dorsal spines; lateral spines 
absent except one short apical pair on segment 9. Median dorsal line 
defined by a smooth obtuse ridge, more distinct posteriorly. 
Of the five nymphs of the Arigomphus group now known, 
cornutus is the largest. The total length for each is approximately 
as follows: australis 30 mm, furcifer 34-35 mm., villosipes 37 mm., 
pallidus 38 mm. and cornutus 40 mm. 
The nearest relative of cornutus is without doubt G. furcifer. 
Walker (1904) described the nymph of the latter. Besides 
differing in greater length, the nymph of G. cornutus is a trifle 
less acuminate than its relative. Proportionately, segments 
9 and 10 of furcifer are equal in length to 6, 7, and 8 taken to- 
gether; in cornutus 9 and 10 taken together are distinctly shorter 
than the preceding three segments combined. Small lateral 
spines are present on segments 8 and 9 of furcifer, very minute 
on 8; in cornutus the spines are similar. 
G. villosipes appears to be similar to G. furcifer. We have not 
seen nymphs of this form. 
COMPARISONS, SYNONYMY, ETC. 
Gomphus cornutus was described by Tough in 1900 from two 
males, taken in Illinois. His description was reproduced by 
Williamson in the same year in the Proceedings of the Indiana 
Academy of Science. Williamson added some remarks as follows: 
“Mr. Tough writes me that he thinks he has since taken the 
female of this species. The occiput is high, rounded, and in 
front is a triangular pyramid, its base bounded by the line be- 
tween the vertex and occiput, and by lines drawn from the ex- 
tremities of this line to the middle point of the posterior edge 
of the occiput. This species will very probably be found to 
inhabit Indiana.” 
