TrIACANTIIAGVNA and GvNACANTHA 2 1 



row in the anal loop. The second and third legs are darker than usual, the 

 reddish brown of the femora being darker with the apical black more ex- 

 tensive. Rut I believe the species is certainly difcleri. 



Several evenings at Palma Sola, returning home about sunset, walking 

 on the railroad track through the practically continuous forest which sur- 

 rounds the village, suddenly before us, near at hand and as far as we could 

 see down the track, would appear the w^idely darting forms of Triacantha- 

 gynas. Even when seen in numbers each individual's flight was too erratic 

 and independent to permit calling the assemblage a flock. One evening 

 they were especially numerous. We tried striking at individuals, and we ran 

 down the track beating back and forth with the net, but two of us doing 

 our best failed to catch a single one. Returning later one evening I ran 

 along the track striking right and left as rapidly as possible and thus by sheer 

 good fortune netted two individuals, a male each of dltderi and of caribbca. 

 The single specimen taken at Puerto Barrios was associated with T. septima. 

 I had been catching specimens of septima since about sundown and when 

 ditdcri was captured it had grown so dark I could see individuals only when 

 they came between me and the clear sky. I think all the other specimens of 

 ditzleri we captured were taken in the forest where, when flushed, they 

 usually flew a short distance and alighted on some twig or stem, or even 

 tree trunk, in characteristic aeshnine position with down-hanging abdomen. 



Material examined: Guatemala, Cayuga (Schaus and Barnes, April, i 

 female. August 27, i male, September 16, i female, A. N. S. ; first two 

 recorded. Calvert 10, as T. trifida, the female of September 16 as septima), 

 Puerto Barrios (June 23, 1909, i male, E. B. W.) ; ColoiPibia, Puerto Berrio, 

 Dept. Antioquia (January 31 and February 8 and 21, 1917, 3 males, 3 fe- 

 males, E. B. W.) ; Venezuela, Palma Sola, Dept. Falcon, (March 6, 1920, 



1 male, E; B. W.), El Guayabo, Dept. Falcon (April 22, 1920, i male, E. B. 

 W.), La Fria Dept., Falcon (April 12, 13, 16 and 17, 1920, 4 males, 2 females, 

 E. B. W.) ; British Guiana, Bartica (H. S. Parish, May 28 and June i, 1901, 



2 males, O. S. U.) ; Dutch Guiana (i male, i female, O. S. U. ; i male, det. 

 by R. Martin as trifida, Ris ; i male, E. B. W.), Paramaraibo (Miss K. 

 Mayo, I female, A. N. S.) ; Brazil, Para (C. F. Baker, i female, E. B. W.), 

 Tapajos, Amazon, Monte Christo (A. H. Fassl, May, 1920, i female, Ris), 

 Porto Alegre, Rio Grande de Sul (J. D. Haseman, January 21, 1909, i male, 

 Ace. 3768, Carn. Mus.), Blumenau, Santa Catharina, (i male, E. B. W.), 

 Chapada (i male M. C. Z., recorded, Calvert 6, as trifida). See also discus- 

 sion above of specimens in the de Selys' Collection. Type male and allotype 

 female, La Fria, Venezuela, April 17, 1920, E. B. W. Named for William 

 Howard Ditzler, who, as a member of the University of Michigan Venezu- 

 elan Expedition collected, among many other dragonflies, the type of this 

 handsome species. 



Needham's Figure 3, Plate XXXIX. A Genealogic Study of Dragon- 

 Fly Venation, is probably of the wings of this species. 



