29O ENTOMOLOGICAL NEWS. [J u ty> ' I2 



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. Picaclo, 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 Erpetogomphns, 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). 



$ 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 



