428 PROCEEDINGS OF THE NATIONAL MUSEUM vol. i06 



which is of medium width and with shallow emargination. The 

 anterior plate is wider than long, with sides converging both forward 

 and backward from tips of premarginal carinae (fig. 3,6); the inner 

 carinae are narrow, widely separated on anterior plate; only the tips 

 of the coni are visible from above; eye small but Avith seta short 

 and thick. 



Prothorax rather narrow (male, 0..34; female, 0.37), with convex 

 sides and posterior margin slightly concave. 



The pleurites are narrow dorsally and dark brown, but three times 

 as wide ventrally and not much paler; the dorsal "heads" taper to a 

 slender point, curving inward more noticeably in the male, while the 

 ventral portion is longer, bluntly pointed, and faintly pigmented. 



The abdominal chaetotaxy is quite long, especiall}^ the patch of eight 

 setae on each side of ventral face of segment VIII that extend more 

 than half way across the segment. Posterior margin of genital plate 

 is V-shaped, rather short, and with setae widely spaced. 



In the male, segment VIII is unusually large, with sides straight 

 to the rounded tip. The genitalia are quite distinctive and need no 

 description (fig. 6,/). 



The species is represented by the female holotype, male allotype, 

 and one male paratype. 



Formicapfiagus splendidus, new species 



Figures 3, a; 5,g 



Type: Female adult from Pittasoma michleri zeledoni Ridgway, 

 collected by the author at Rio Sicsola, Panamii,- Sept. 10, 1904 

 (author's collection). 



Diagnosis: The body and head are almost the same size as the 

 females of magnus (body, 1.95 X 0.62; head, 0.55 X 0.532), thus 

 being one of the largest known species. 



The temples are slightly swollen; the preantennal margins of head 

 form almost straight lines (slightl}^ concave) from coni to tips of 

 frons, which is of medium width and shallow emargination. Anterior 

 plate as wide as long, slightly expanded laterally at middle and with 

 a wide, V-shaped, darker band across anterior portion (fig. 3,o). 

 The inner carinae are narrow basally but wide over anterior plate, 

 with large incrassations ; eye prominent, with seta short and thick. 



Prothorax large (0.21 X 0.33) with convex sides; pterothorax of 

 medium size, with straight sides and postenor margins and with lateral 

 angles narrowlj^ rounded. Abdominal sderites normal; dorsal face 

 of pleurites narrow and black, ventral face twice as wide as dorsal 

 face and brown; tergites set closely together, both transversely and 

 longitudinall}^ Segment VIII unusually short and wide; ventral 



" This host was collected ou the west side of the KIo Sicsola in territory which at that tiiue belonged to 

 Costa Rica but has since been ceded to Panama. 



