422 PROCEEDINGS OF THE NATIONAL MUSEUM vol. i06 



with sides straight and parallel for greater portion; the inner carinae 

 are unusually narrow, ver}'' straight in anterior portion and lack 

 entirely the large incrassation so prominent in most species (fig. 4,c); 

 antennae unusually thick (compare c and d of fig. 4; d being about 

 normal); eye obsolete, but setae present; coni small. 



Prothorax small, especially short (0.13X0.26); pterothorax wdth 

 straight, divergent sides, broadly rounded lateral angles, an(] sides 

 of posterior margin flatl,y convex with rounded median tip. 



Color of abdomen as in preceding species, with pleurites of average 

 size, largely pitchy black dorsally, and but slightly wider ventrally, 

 more so in posterior portion; "heads" short and bluntly pointed on 

 dorsal face but much longer ventrall^^, some of them curving outward 

 apically. 



Abdominal setae shorter than average; the ventral patches on sides 

 of sternite VIII average nine ' in number, are short, and most of 

 them point backward; there are also five dorsal setae in a transverse 

 row on each side of segment VIII, all set in small, clear pustules. 

 These latter setae are present in all species, but the number varies 

 (usually three) with inner one alwaj^s the longest. 



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

 and one male paratype. 



Formicaphagus peruvianus, new species 



Figures 2,c; 6, a 



Type: Male adult from Myrmotherula schisticolor interior (Chap- 

 man), collected by the author at Enenas, Peru, Mar. 3, 1930 (author's 

 collection.) 



Diagnosis: One of the group with small head, only minutus and 

 angustifrons having smaller (0.412X0.402). Differs from angustijrons 

 in having whole occipital margin of head convex instead of deeply 

 emarginate at sides of occiput; the anterior plate is much wider in the 

 anterior portion than in the posterior portion, the reverse of angustifrons 

 (see figs. 2,c and 2,d); the head is much wider at coni (0.337 against 

 0.295); pterotliorax shghtly larger than both species mentioned above, 

 with sides slight!}^ concave and posterior margin straight. Abdomen 

 longer than in angustifrons and minutus, and wider than in augusti- 

 Jrons; color normal; pleurites large and pitchy black dorsally, with 

 sternal portion considerably^ wider; "heads" of pleurites short both 

 dorsally and ventrally, the ventral portion being weakly pigmented. 



In the genitalia the basal plate is \Qvy sunUar to that of clypeatus 

 and angustifrons, but longer than in latter; the parameres are similar 

 in size and shape to those of angustifrons but lack the dark marginal 



' Segments VH and Vin are fused so closely that the line of fusion is not always visible. The setae are on 

 segment VIII. 



