416 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loe 



wide (0.553 X 0.532); the anterior plate of same shape as in laemo- 

 stictus but much larger and without anterior shield ; the premargina.l 

 carinae are wide but pigmented only along the inner margin, while the 

 nodi are chitinized in posterior portion only. The incrassations on 

 inner carinae, over anterior plate, are smaller than usual; the pre- 

 antennal margins of head slightly undulating, with sides of anterior 

 plate extending latterly beyond line of head; postmarginal carinae 

 also present, but differing in pattern from those of laemostichis (see 

 hg. 2,6). 



Prothorax with sides flatly convex; pterothorax very wide (0.47) 

 with convex sides, that portion posterior to the lateral angles shortened 

 and with sides straight to rounded median tip (fig. 2,b). 



Abdominal pleurites narrow, ventral portion scarcely wdder than 

 dorsal; "heads" short, tapering to a slender point which curves 

 inward and backward, forming a semicircle. Structure of tergites 

 and sternites obscured by foreign matter. Setae along posterior 

 margin of genital plate short and thick; ten ventral setae on sides of 

 sternite VIII, paralleling lateral margin, and two more between this 

 line and the margin, all pointing diagonally backward and inward 

 and all longer than those of laemostidus. 



The species is represented by the female holotype only. 



Formicaphagtts angiistifrons, new species 



Figures 2,d; 5,c; 6,(1 



Types: Male and female adults from Myrmeciza h. hemimelaena 

 Sclater, collected by the author at Santa Ana, Rio Coroico, Bolivia, 

 July 21, 1934 (author's collection). 



Diagnosis: One of the smallest species of the genus (body of male, 

 1.25 X 40; of female, 1.40 X 0.40; head of male, 0.39 X 0.39; of female, 

 0.417 X 0.417); the abdomen of the female is longer but no wider 

 than in the male. 



Temples rounded; occipital margin deeply reentering at sides of 

 prothorax, but occiput convex; frons very narrow; preantennal 

 margins slightly concave; anterior plate small, widest in posterior 

 portion and converging sharply to the narrow tips; premarginal 

 carinae narrow, as well as the inner carinae which support the an- 

 terior plate; incrassations elongated and not reaching to the lateral 

 margins of the plate; no postmarginal carinae; eye very small, with 

 short, thickened seta at anterior corner. (In the figure of the head 

 of this species the temporal and occipital carinae occupy reversed 

 positions.) 



Thoracic segments small, with sides slightly convex; pterothorax 

 only 0.31 in widtli in the female and 0.29 in male; posterior margins 

 straight and median point rounded. 



