612 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxviii. 



This indicates plainly that the genus has a development similar to 

 that of the other members of this subfamily. 



Posterior sinuses shallow with divergent sides; median lobe four- 

 sevenths the entire width, projecting far behind the lateral lobes, with 

 nearly straight, inclined sides, and an emarginate posterior border. 

 Lateral lobes short and well rounded. Thoracic area very small, the 

 groove which defines its anterior border reaching onl}- ashoi't distance 

 in front of the posterior sinuses, or about one-third the entire length 

 of the carapace. 



The longitudinal grooves separating the lateral from the cephalic 

 areas are not well defined and are consequently difiicult to trace. 

 Eyes small and situated well forward. 



Free thoracic segment cylindrical, about one-fourth the width of the 

 carapace, contracted considerably just befoi'e joining the latter and 

 prolonged posteriorly into a narrow, thread-like neck, nearly twice 

 the length of the rest of the body. 



The fourth legs are attached close to the carapace just back of the 

 constriction. 



Genital segment approximately an ellipsoid, two and a half times as 

 long and twice as wide as the carapace. It is flattened somewhat dorso- 

 ventrally and has three lobes on the posterior margin, a short blunt 

 one at the base of each of the egg cases and a smaller median one. 

 The dorsal surface of this segment is marked by two ridges which 

 start from the center of the lateral margins on either side and curve 

 in toward each other and pass backward close together alongside the 

 median line to the posterior median lobe. The areas at the posterior 

 end of the segment outside these ridges are darker in color than the 

 rest of the segment, and their surface is wrinkled irregularly. They 

 contain the ovaries and the internal oviduct. 



The abdomen is an elongated spindle, nearly twice the length of the 

 genital segment and half its width, unsegmented. It is contracted 

 into a ver}^ narrow wasp-waist where it joins the genital segment and 

 tapers evenly and gradually toward the posterior end. It is attached 

 to the ventral surface of the genital segment, a short distance in front 

 of the posterior end, and in a side view stands out nearly at right 

 angles to the longitudinal axis of the segment. 



Anal papilla} linear, almost thread-like, but quite long and tipped 

 with three short sette. Egg tubes narrow, only one-quarter as wide 

 as the abdomen but about the same length, each containing 40 to 50 

 eggs. 



Anterior antennae the same length as the frontal plates; basal joints 

 thick, conical, and heavily armed with plumose set^; terminal joints 

 the same length as the basal, C3dindrical, and bluntly rounded at the 

 ends where they show the usual nonplumose seta?. 



Frontal plates peculiar in that the outer portion between the lunules 



