( 318 ) 



and is densely covered with fine hairs, as are all the tarsal segments. The second 

 segment is only half the length of the first segment, its longest apical bristle 

 not quite reaching the middle of the fourth segment. The fifth segment (exclusive 

 of claw) is a little longer than the third. 



Modified Segments."' — In the male the eighth tergite hears at its hinder 

 edge twelve to fourteen long bristles, placed quite close together. Tlie eighth 

 sternite is rounded and truncate at the end, with its upper corner produced into 

 a lobe, whicli is densely beset with long bristles at its edge (fig. 2). The ninth 

 tergite is very characteristic. The process of the clasper is acuminate, the 

 manubrium being strongly curved and obtuse at the end. The movable finger is a 

 little shorter than the process of the clasper, and somewhat shaped like a half- 

 crescent, being convex on the hinder and concave on the anterior or " upper" side. 



In the femnle the ajiicul edge of the eighth tergite (fig. 3) is sinuate. The 

 number of bristles is not quite constant. There is one long solitary bristle beneath 

 the stigma. The three upper bristles situated near the apical edge are short and 

 stout. The eighth sternite bears one very small hair at the apex. 



Lengtii, 3'3 mm. 



We received ten specimens of tliis interesting species from Mr. G. F. Dippie, 

 taken from Lagomys princeps : — 



4 66, Canadian National Park, Alberta, Canada, July 26, 1899. 



^ + + » T> V )T »J »' J) )J 



1 ?, Banff, Alberta, Canada, July 26, 1899. 



2. Stephanocircus thomasi spec, nov.f (PI- IX. fig. 4. 5). 



Head. — The frontal jjortion of the head (fig. 4) is very long. It is again 

 separated into an upi)er part (H) corresponding to the " helmet "of the other species 

 of StcpliaiiorircHs and into a lower or genal part (G). The upper part bears at its 

 ventral and posterior edges a series of heavy spines (fig. 4). Eight of these are 

 situated at the ventral edge. Of these spines, the first is situated apart from the 

 rest, the one .spine at the angle being about twice as Jong as any of the other 

 spines. The three spines at the hinder edge are short, gradually decreasing in 

 length. There are no genal spines. The palpi are shorter than the rostrum, the 

 latter reaching beyond the apex of the forecoxa. 



Thorax. — The pronotal comb consists of twenty-seven teeth. The epimerum of 

 the metathorax bears two vertical rows of hairs, consisting of three hairs each, and 

 in addition a single ventral hair. 



Abdomen. —The first four tergites bear a comb consisting of 26, 22, 21 and 

 12 teeth respectively, the teeth standing close together. The seventh tergite has at 

 its ajucal edge on each side three or four long bristles, of which the second is the 

 longest and the most dorsal one the shortest. 



The first abdominal sternite bears a curved row of about seven bristles on each 

 side, and a number of shorter hairs situated immediately in front of this row. The 

 third, fourth and fifth sternites have three or four bristles. 



Legs. — The bristles of the legs are slender, those of the very slender tarsi being 

 also extremely short (tig. 5). 



* The more posterior segments, that is to yay, segments 8 to 10, of the majority of the 

 Siplwnuptera, are considerably modified for sexual purposes, and are throughout the present article 

 described separately from the rest. 



t This species is named in honour of Mr. Oldfield Thomas, F.E.8., the British Museum. 



