178 bulletin: museum of comparative zoology. 



Head subdensely punctate, the punetae being moderately fine and 

 not sharply impressed or limited. 



Antennae composed of seventeen articles of which the first two are 

 glabrous and shining, the others being densely pubescent as usual. 



Dorsal plates from the fifth to the twentieth with the two longi- 

 tudinal sulci present and complete; fine. Lateral portions of plate 

 from the fifth caudad depressed leaving the lateral margin distinctly 

 elevated, especially in the middle and caudal regions, but true margina- 

 tion present only on the twenty-fii'st plate. The depressed lateral 

 portion of the plate rugose, the main rugae being longitudinal. The 

 elevated margins, the rugae, and, less extensively, the intermediate 

 surface, roughened with series of numerous spinulose points. From 

 the fifth or sixth plates on a median longitudinal keel is indicated, 

 this being at first obscure but becoming more and more distinct 

 caudad, while at the same time on each side of it and just mesad of 

 the sulcus appears another keel, the three keels being distinct on the 

 caudal segments; the keels are scabrous like the lateral portions of 

 the plates. Last dorsal plate with the posterior edge moderately 

 bowed out caudad and mesally truncate. With three longitudinal 

 keels corresponding to those of the other plates extending from the 

 anterior margin caudad two thirds the length of the plate, the plate 

 caudad of their ends having a shallow pit-like depression. Keels and 

 general surface scabrous. 



Sulci of ventral plates detectable only as very short traces at the 

 anterior border of each. With tliree pit-like depressions arranged in 

 a triangle as usual, these being of but moderate depth and size and not 

 coalesced. In addition there are tliree other depressions along the 

 caudal border separated from those of the triangle by a distinct trans- 

 verse sulcus. On some of the more caudal plates the anterior median 

 pit may be extended a considerable distance caudad as a median 

 furrow. Last ventral plate conspicuously narrowed caudad, the sides 

 being convex at anterior ends but straight for most of their length. 

 Caudal margin with lateral halves straight and meeting in the middle 

 in a slightly reentrant angle. No distinct median sulcus present. 



Coxopleurae a little extended caudad at caudomesal corners which 

 are simply rounded, no distinct process being developed, wholly 

 unarmed. 



Only the first pair of legs with two tarsal spines. Second to eigh- 

 teenth pairs with a single tarsal spine. Nineteenth to twenty-first 

 pairs unknown, being absent from the only specimen known. 



Length 57 mm. 



