500 bulletin; museum of comparative zoology. 



anterior border meeting a semicircular transverse sulcus the convexity 

 of which is caudad. Sulci on the remaining plates parallel or very 

 nearly so. On the third plate an oblique sulcus runs from the anterior 

 end of each longitudinal sulcus obliquely ectocaudad. Some tergites 

 of the posterior median region may show two longitudinal sulci close 

 together and embracing between them a slight median ridge, but no 

 true keel is present on any of the plates. The last dorsal plate with 

 the caudal margin arcuate, the median portion protruding convexly 

 with each lateral end becoming transverse or nearly so. 



Ventral plates smooth and unfurrowed excepting for a transverse 

 subsemicircular impression or furrow toward anterior end of each 

 plate, this furrow usually more distinct in caudal region. Last 

 ventral plate nearly equal in length and breadth. Sides convex, 

 strongly converging caudad. Caudal margin mesally angularly 

 emarginate. 



Coxopleural processes moderately long, straight; the distal spine 

 slender and acute. Process armed on ventral surface mostly with two 

 spinules, but sometimes with only one. Caudal border of coxopleura 

 also bearing usually two spinules. 



Spiracles typically circular; the first very much larger than the 

 succeeding ones, sometimes appearing more or less elongate. 



Tarsi of all legs biarticulate. Second tarsal joint of anterior legs 

 bearing a slender ventral spine near middle. Tibia with a small 

 ventral but no lateral spine at distal end. Femora of all legs with 

 ventral spinule at distal end. Prefemora with mostly two or three 

 ventral spinules. 



Penult legs with femur and prefemur bearing a considerable number 

 of spinules chiefly on dorsal and mesal (caudal) surfaces. 



Prefemur of anal legs bearing on ventral surface a longitudinal 

 series of four long spines of which the most distal is farther ectad than 

 the others and is at the very distal end of the article; these spines 

 distinctly shorter than the diameter of the article. Femur with a 

 similar ventral series of three spines nearly of same size as those of the 

 prefemur; of these the most proximal is farther ectad than the others 

 and the most distal one is about one fourth the length of the article 

 from its distal end. Femur and prefemur in addition bearing numer- 

 ous spinules on ectal and dorsal surfaces. Other joints unarmed. 

 Tibia longer than the femur and longer than the first tarsal joint in 

 about ratio 13:10. First tarsal joint much more slender than the 

 tibia; somewhat angularly extended ventrad at distal end. Suc- 

 ceeding portion of tarsus abruptly very much more slender, propor- 

 tionately short, commonly not much differing in length from the 

 femur; composed of from five to eight distinct articles. Bristles 

 sparse, moderate in length. 



Length up to 22-23 mm. 



