412 PROCEEDINGS OF THE XATIOXAL MUSEUM vol. los 



This genus seems to be related to the philopteroid group, and re- 

 sembles superficially the genus Sturnidoecus, from which it differs, 

 however, in many important characters, as will be shown. 



Head about as wide as long, with circular, expanded temples 

 more or less as wide as the abdomen in the male, slightly less in the 

 female. Preantennal portion of head converges sharply to a narrow, 

 bifid frons, more or less deeply incised. Premarginal carinae usually 

 wide but short, terminating at the preantennal suture encircling th(> 

 posterior portion of the anterior plate, which is flatly convex and does 

 not extend beyond the entrance to the bucal cavity. The anterior 

 plate is uniformly pigmented, Avithout dividing lines, with half its 

 length extending beyond the tips of the premarginal carinae, and with 

 exposed portion encircled by a narrow hyaline border. 



The inner premarginal carinae are well developed, extending from 

 anterior mandibular condyles and base of premarginal nodi to tips 

 of frons. In most of the known species there is a conspicuous, heavily 

 chitinized, oval incrassation on the outer side of these carinae, in 

 median portion of anterior plate. A sharply defined suture cuts 

 diagonally across the premarginal carinae, just in front of nodus, from 

 the margin of the head to a point midway between the mandibular 

 condyles. The temporal carinae (dorsal) are absent, but in all 

 species a well-defined carina curves backward and inward from the 

 premarginal nodus to the posterior mandibular condyle (see figures); 

 the occipital carinae (sternal) are always present, rather narrow, and 

 poorly chitinized, ending usually at anterolateral margin of prothorax. 

 Gular plate large, varying greatly in detail of attachment to pro- 

 thorax. 



Prothorax small, much wider than long, and more or less quad- 

 rangular. Pterothorax, with strongly divergent sides, straight to 

 convex, and, with few exceptions, posterior margin produced to a point 

 medially. 



Abdomen elongated oval in both sexes, with sharply defined, deeply 

 colored pleurites which are furnished with conspicuous "heads." 

 Tergites lightly chitinized and separated medially; sternites entire but 

 separated from pleurites and almost invisible except for the genital 

 plate and one or two sternites anterior to it. Terminal abdominal 

 segment of female much wider tlian long, with rounded sides and 

 slightly indented tip. In the male, segment VIII is small, with con- 

 cave sides and rounded tip. Chaetotaxy of the abdomen (in posterior 

 half) differs in the sexes. In the female there is a sternal row of 

 seven to nine fine setae on each side of segment VIII, in the anterior 

 portion, which point inward and backward and which must not be 

 confused with the pair of heavy spines found in this area in the genus 



