24 E. 15. Williamson 



(March 4. 6 and 9, i<j20, i male, 3 females, i fjnrile shot by 11. 1j. luiker 

 in forest. E. B. W.) ; Boqueron, Dept. Yaracuy (March 16, 1920, i male, 

 E. B. W.), Aroa, Dept. Yaracuy (March 14, 1920, i female shot by H. 

 B. Baker in forest, E. B. W.) ; Dutch Guiana (Thorey, i male, M. C. Z.) ; 

 Bracil^ (Heyer, i male, labelled ''''Gynacantha data Ha.i^en". and 1 male 

 labelled *'Aeschna augusta Hagen," M. C. Z.), Bom Jesus de Itabapoana, 

 Rio Janeiro (Zikan, July 27, 1905, i female, Ris). The single s])ecimen 

 from Guatemala is recorded as trifida in Calvert 10; and the five males and 

 one female from Mexico, Colombia (Turbo), Dutch Guiana, and P.razil 

 (Heyer, M. C.-Z.) are recorded as the same species in Calvert 6 and ir. 

 See also discussion above of specimens in the de Selys Collection. Type 

 male and allotype female, Palma Sola, \'enezuela, March 6, 1920, E. B. W. 

 It should be noted that some of the above material is teneral and other- 

 wise in a bad state of preservation, making detenninations difficult, and the 

 female of T. satyrus is not known and may be confused as a female of this 

 or other species. For these reasons the records for Mexico, Guatemala, and 

 Rio Janeiro, Brazil, are open to question. 



TriacautJiagyiia trifida Rambur 



I, 2, 5, 6 (Chapada male is ditzleri; Mexico, Colombia, Dutch Guiana and Brazil 

 [Heyer] specimens are caribbea), 8 (is satyrus), 9 (is satyrus), 10 (male and 

 April female are ditzleri; August female is caribbea), 11 (see 6 above), 12, 13, 

 16, 20, 23, 25, 26, 34, 35, 2^, 39; all references in the literature to specimens 

 outside the range of T. triUda, as indicated in the material studied in this paper, 

 are probably to some other species than trifida. 



Abdomen male 42-45, female 47-50; hind wing male 41-43, female 44-47; 

 superior appendage male 6-6.3, female 9-10.6; stigma front wing 3.3-4.2. 



I have seen only preserved material. The coloration is essentially the 

 same as in T. ditderi, but the dark dorsal thoracic area, in those specimens 

 where the pattern is discernible, is triangular, with the lateral edges nearly 

 or quite straight, not nipple-shaped as in T. ditderi. 



The wings are hyaline to yellowish brownish tinged. Twelve wings of 

 males and twelve wings of females each had three cells in the most anterior 

 row of the anal loop. In the males there were invariably two cells just 

 posterior to A between the anal loop and the anal triangle, and in the female 

 there were four cells posterior to A between the wing base and the anal loop. 

 In three front wings of males one front wing of a female and two hind 

 wings of males there was in each case a single double cell between M^ and 

 Rs; in all the other wings there was a single row of cells throughout. For 

 a note on the basal forking of Rs see text under T. ca'ihbca. See also last 

 paragraph of text under T. ditzleri. 



In the specimens examined there were no spines or teeth on the ventral 

 margins of abdominal segment 2 in the male, and the auricles were armed 

 each with three denticles or with three and the vestige of a fourth. Append- 

 ages of female elliptical, a low median longitudinal carina, of nearly uni- 

 form width throughout after the gradually tapering basal third ; apex rather 

 abruptly rounded, extreme apex acute, maximum width 1.3. 



