290 ENTOMOLOGICAL NEWS. [July, 12 
cited below under E. elaps’—a single male taken by the late 
Professor Biolley, in May, 1905, now in the British Museum 
of Natural History as part of the Godman-Salvin collection. 
During the year which I spent in Costa Rica, I only once 
saw an insect which I thought might have been an Erpe- 
togomphus. This was on the southern edge of Cartago, but I 
was unable to capture it, and repeated visits to the same spot 
on subsequent days failed to rediscover it. Its identity is 
therefore entirely uncertain. 
In July, 1911, Professor J. Fidel Tristan, Senora Tristan and 
Senor C. Picado, went to Oricuajo, a farm belonging to Senor 
Santiago Guell, on the Pacific side of Costa Rica, between the 
Rivers Machuca and Jesus Maria, where they unit. Professor 
and Senor Tristan were here from July 5-10, and made a collec- 
tion of Odonata which Professor Tristan subsequently sent to 
me. Among them was a male and a female Erpetogomphus, en- 
closed in the same envelope, so presumably taken pairing. This 
pair not only confirm the existence of the genus in Costa Rica, 
but are of an undescribed species which, in honor of my friend 
and companion on many a delightful excursion, I herewith 
describe as 
Erpetogomphus tristani, n. sp. (Plate XVII). 
é Vertex, clypeus, labrum, occiput and genae dark brown. Frons 
bright green, except for a superior transverse dark brown stripe in 
front of the antennae which is confluent in front of each eye with a 
narrower transverse dark brown stripe along the inferior margin. 
Labium, maxillae and bases of the mandibles pale yellow, but the 
apices of all brown or black. A nearly straight transverse ridge on the 
vertex behind the ocelli, forming a tubercle bearing some long dark 
hairs behind each lateral ocellus, but concealing only a small part 
of the occiput when the head is viewed from in front (Fig. 2). Hind 
margin of the occiput almost straight, curving slightly upward at each 
eye, with a row of moderately long dark hairs. 
Fore and hind lobes of the prothorax pale green, the former tinged 
with pale brown on the sides. Middle lobe pale brown, a pair of sub- 
median dorsal dots and a larger spot each side pale green. 
Thorax (meso-metathorax) with the mid-dorsal carina, borders of 
the ante-alar sinus, a mid-dorsal and a humeral stripe, and stripes on 
the first and second lateral sutures and along the ventral margin of 
the metepimeron, dark maroon brown. The median brown stripe is 
