1909.] 9 



along the ventral margin. ? . The eiglith tergile lias more bristles than in iS. 



minerva, there being about 24 long ones and several short ones, besides tiie short 

 slender bristles placed at the truncate apical margin of the segment. Tlie anal 

 sternitc lias about eight bristles altogether. The stylet is a little more than twice 

 as long as it is broad at its base. The receptacuUun serainis has almost the shape 

 of a stocking, as is the case in S. minerva and mars. Length, S 2"1 mm., $ 3 mm. 



We have a long series of this species from Porvenir, Buenos 

 Aires, Argentina, taken oft' Didclphis crassicaudata, collected by Dr. 

 K. Wolffhugel, 4th April, 1905. 



'1. — Stephanociecus wolffsohni, spec. nov. (figs. 2, 3). 

 A very distinct species. 



i/eaeJ;— The helmet resembles that of the other three known American Ste- 

 phanocircus {minerva , mars, and the above described new species), but is narrow, 

 and bears a comb of but 11 or 12 spines The central spines of this comb are 

 rounded at their tip, the seventh spine from beneath being the longest, the width 

 of the helmet measured from the base of this spine equalling the length of that 

 spine. There is a comb of five genal spines, the uppermost spine being narrow. The 

 first segment of the maxillary palpus is but little longer than the second. The 

 rostrum nearly readies to the apes of the fore coxa. The first segment of the an- 

 tenna is less than twice as long as it is broad, the second segment also being sliorter 

 than in the other American species. 



Thorax : — The pronotum has a comb of 15 pointed spines. The dorsal bristles 

 in the postei'ior row of the meso- and metanotum are somewhat longer than the 

 lateral ones in the $ . The epimerum of the metathoras has two rows of bristles, 

 containing in the $ four and in the ? five bristles each. The episternuin of the 

 metathorax as well as the sternum bear each two strong bristles. 



Abdomen : — There are two rows of bristles on the tergites, the first and second 

 tergites having some additional bristles in front of the rows. In the (? the first to 

 fourth tergites have the doi'sal bristles very much prolonged, these bristles forming 

 a kind of mane. The seventh tergite has but one apical bristle in both sexes ; this 

 bristle is on one side of our only S broad, almost blade-like in side view. The 

 sternite of the second segment has a ventral pair of bristles. On the sternites of 

 segments three to seven of the <? are three brislles on each side, the sternites of 

 segments three to six of the ? bearing four bristles with two to four smaller ones 

 in front ; on the seventh segment of the ? there are two rows of about seven 

 bristles on each side. 



Legs: — The hind coxa is less broad than in the other American species of this 

 genus. The hind femur bears two ventral and two or three lateral bristles poste- 

 riorly near the apex, there being no bristlas further front and on the sides. The 

 tibiae and tarsi resemble those of <S. mars, Rothsch. ; the long bristles, however, are 

 a little shorter than in that species. 



Modified segments :— S . The main portion of the clasping organs is a large 

 clasper (fig. 2), which is rounded at the apex, and bears along the apical edge a 

 regular row of very long bristles. The moveable process F cannot clearly be made 



