268 PROCEEDINGS OF THE ACADEMY OF [May, 



Genital valves ( = external gonapophyses of 9) reaching almost, 

 but not quite, to the level of the hind end of 10, brownish, ventral 

 margin spinulose, the palps slender, reaching beyond the level of the 

 hind end of 10, but not of that of the anal tubercle ( = 11), darker 

 in color. 



Of the two females from Tumatumari, one lacks all pruinosity 

 on the body and the pterostigmata, the other has a small quantity 

 on the rear of the head only; they appear to be the most immature 

 of their sex in the present material. 



Dimensions. — Abdomen cf 26,5-34, 9 24,5-25,5; hind wing 

 cf 21,5-25, 9 20-22.5 mm. 



Habitat. — British Guiana: Wismar, January 30 and 31, three 

 males, three females; Rockstone, February 1, six males, one female; 

 Tumatumari, February 5, one male, February 7, one female, February 

 11, one male, one female; Potoro Landing, February 10, three males. 

 Collectors, L. A, and E, B, Williamson and B. J. Rainey, 1912. 



Type. — A male from Wismar, January 30, abdomen 30.5, hind 

 wing 22,5 mm, long, in the collection of Mr, E. B, Williamson, of 

 Bluffton, Ind, The other material in the cohections of Mr. WiUiam- 

 son and of the author. 



Habits. — The Tumatumari female of February 11, the youngest 

 of her sex of the present material bears this label by Mr. E, B, Wil- 

 liamson: "taken at top of trail 2| mile past Tiger Creek trail on 

 twig." A male from Potoro Landing, the smallest of his sex in all 

 the present lot has this note by the same collector: "On ends of 

 twigs wings expanded usually in shade," 



Mr, Williamson has kindly furnished the following notes with 

 reference to the habits: "At Wismar back from the river, across 

 the railroad tracks and south of the eminence on which stands the 

 manager's (Mr. Croombie's) house, is a brushy swampy woods, 

 traversed by numerous small streams which head in small ravines 

 with abrupt and rocky ends or pockets. These streams at the 

 season I was there were small and frequently disappeared and hence 

 were followed with some difficult}^ in their upper course. All were 

 short and were intermingled in the lower (east) end of the woods 

 where the ground was swampy and the footing treacherous. The 

 Agrionines were found usually near the upper ends of the streams 

 below the rocky pockets. 



"At Rockstone the railroad track was followed back toward Wismar 

 where two or three streams, small at this season, cross the track at 

 intervals, flowing in a northerly direction. These streams were 



