122 



Alexander PetriDikevitch, 



segments with a heavily thickened posterior edge. The first, second, 

 and third tergites procurved, the fourth with a procurved anterior 

 and recurved posterior edge. The following tergites slightly recurved. 

 Sternum elongated, divided into three areas of which the middle one 

 is hexagonal and the two others pentagonal. Abdomen oval, with ten 

 tergites and seven sternites. Genotype M. triangularis n. sp. 



Metatarbiis triangularis n. sp. 

 Plate XI, figs. 66, 67;. text figs, yj, 78. 

 The type specimen of this species is in the Peabody Museum, 

 No. 182. It is somewhat deformed, so that the left half is narrower 



Figure jj. — Mefatarbus (rtangu/aris n. sp., holotype, Peabody Mus. No. 182, 

 dorsal surface. Figure 78. — Some, ventral surface. X — 



than the right half, but otherwise well preserved. Total length 

 17.5 mm. Cephalothorax triangular, posterior edge procurved, pos- 

 terior corners rounded, sides curved. Length in median line 7.5 mm. 

 Maximum width 8.0 mm. Eyes absent. Abdominal tergites ten. 

 Only four anterior tergites short and with hea\dly thickened posterior 

 edge. First, second and third tergites procurved, fourth with a 

 procurved anterior and recurved posterior edge. The follo\\ing ter- 

 gites slightly recurved, Sternites seven. The first sternite trian- 

 gular. Two converging lines divide the ventral surface of the ab- 

 domen into three fields. Anus round, ventral in position, its oper- 

 culum impressed on both the dorsal and ventral surfaces. Sternum 

 long, di\dded into three areas of which the middle one is hexagonal. 



