TWO NEW LICE. 249 



Chcetotaxy. Female. — Abdomen: Pleurites each with two 

 hairs of much about the same length in each segment. The 

 outline of the tergites at the base of the abdomen is ill defined, 

 and it is therefore difficult to be certain of the exact segmental 

 distribution of the cheetotaxy. It is easier and safer to say that 

 at the base of the abdomen, upper surface, up to segment 2 

 inclusive, there are two parallel longitudinal rows of well-spaced 

 spines, three in each row. The anterior spine of each row is 

 probably metanotal (vide Chsetotaxy, Thorax). On the outer side 

 of each of the two posterior spines is a minute hair. Tergite 3 with 

 a single row of six flattened lanceolate spines. Tergite 4 with 

 two rows (five in the first row, six in the second). Tergites 5 

 and 6 with two rows each (six in each row). In tergite 7 there 

 are five in the first row, four in the second. Tergite 8 has only 

 one row of four. Sternite 2 with two spiny hairs ; sternite 3 

 with two rows (three in the first, two in the second), similarly 

 in sternites 4 to 7. The two spines in row 2 are the strongest; 

 on each side of these, except in segment 7, a small minute hair. 

 Sternite 8, which is the genital plate, is bare except for four 

 minute hairs with large alveoli. A group of short spiny hairs 

 and one larger spine on each side of the genital opening. Three 

 small hairs on each gonopod. 



Male Copidatory Apparatus. (Text-fig. 3.) — This is long and 

 narrow, occupying the three terminal segments of the abdomen. 

 The basal plate, narrow and elongate, broadens elegantly in its 

 posterior half. It lies in segments 7 and 8. The lateral margins 

 are strongly chitinised and rod-like. The paramera lying in 

 segment 9 are bowed outwards at the base but nearly meet each 

 other at the tip. Beyond the point of its articulation with the 

 basal plate, the base of each parameron projects as a process into 

 the intraparameral space. These two processes approach each 

 other but do not meet. Midway the paramera broaden and meet 

 each other beneath the mesosome * so as to join a cavity in which 

 the latter is contained. The penis is a narrow rod with a forked 

 base. The basal forked part may, however, be a separate piece, 

 as there is a distinct transverse line of division between it and 

 the rod of the penis. The mesosome consists of two pieces, a 

 posterior and an anterior. 



Mouth-parts. — For a description of the infra-buccal plate, see 

 Ann. Mag. Nat. Hist. ser. 8, vol. xv. Feb. 1915. 



Notes on the Tracheal System. — The description is taken from 

 an immature specimen in Stage III. There is a pair of spiracles 

 on each of segments 3 to 8 and a pair of larger ones on the 

 mesothorax. The tracheal tubes are very fine and difficult to 

 see through the integument. There are the usual two cardinal 

 trunks, one on each side, joined by a commissure in the last 

 abdominal segment. There is another commissure in segment 4. 

 A lateral diverticulum runs out to each spiracle, and each 



* For the explanation of the use of these terms, see Waterston (1), p. 279. 



