256 
[October 
about 4-^ times as long as wide, and at § the way to their tips gradually taper¬ 
ing to a point which at the extreme tip becomes a small slender thorn. Viewed 
laterally, they are perfectly straight, slightly contracted towards their base and 
tapering towards their tips as before described. Superior anal process short, 
semicircular; the inferior larger but not extending further than the superior, 
triangularly slit to its base lengthways, very pilose and brownish. Vulvar lami- 
and above somewhat cariniform. Occiput with two large transversely arranged 
tubercles behind, the bases of which occupy nearly the whole of its posterior 
surface, and which terminate each in a single sharjj spine inclining a little 
forwards and surmounting its superior edge by a space equal to about 
one-fifth of its entire breadth, the two spines converging at an angle of 
about 60°, so as almost to touch at their extreme tips. Thorax mostly green, 
with brown lines and spots. The abdomen is very clavate, with segments 8 and 
9 much dilated, 8 as broad as long, 10 one-half as long as 9, and it is of a dark 
color, with lateral, rather large, yellowish-brown or snufF-colored patches. Legs 
black. 
Total length 1.80 inch [46 mill.] Front wing 1.25 inch [.32 mill.] Hind wing 
1.20 inch [31 mill.] Hind femur .21 inch [5.^ mill.] Hind tibia .15 inch [3J 
mill.] Hind tarsus .11 inch [2| mill.] Breadth of head .30 inch [8 mill,] One 9- 
Common in the northern part of the State of Maine.” 
I The existence of the Asiatic subgenus Macrogomphus in Horth America 
rests solely upon my authority. The insect referred by me to that subgenus 
{M. spiniceps 9 PP- 389—391) differs from the subgeneric characters laid down 
in the Monographie in a few unimportant points which I have specified, and 
two of which may now be erased from the list, for the following reasons:—l.st 
When M. Selys stated that Macrogomphus has two suhohsolete pale stripes on 
the dorsum of the thorax, I carelessly misunderstood him to mean txvo on each 
side of the dorsum. My species has the number assigned by him to the subge¬ 
nus, viz. one on each side of the dorsum or two in all. 2nd. I have already 
mentioned that the subgeneric character drawn from the protuberance on the 
middle of the 9 occiput was subsequently allowed by M. Selys himself to be 
only of specific value. 
I notice on the abdomen of certain specimens of Mesothemis simplicicollis Say, 
and oi Perithemis Domitia Drury, irregular vein-like dark branches, very simi¬ 
lar to those which I have recorded (p. 390) as found on the thorax of my unique 
Macrogomphus 9 • This of course confirms the opinion expressed by me (p. 
383) that such markings are not markings of external coloration, but connected 
with the internal anatomy of the insect. 
]: The only known species of Epigomphus occurs in Brazil. The is un¬ 
known ; but as the species agrees with Macrogomphus in the two very remark¬ 
able structural characters which I have given under the 2nd division in the 
Table, I have ventured to place it in the same category, though it is possible 
that its inferior abdominal appendages may not be divaricate. M. Selys seems 
more inclined to refer it to the same division as ISTeogomphus, though he places 
it in the body of his book immediately before Macrogomphus. 
