548 MEDICAL ENTOMOLOGY 



contains only the single species acanthopus, Burmeister, with Polyplax 

 as a sub-genus. 



The genus Haematopinus, sensu lato, as thus constituted, and re- 

 presenting the six genera of Enderlein, contains the majority of known 

 species of Anoplura, nearly fifty having been recorded. Man}- of these 

 are well-known parasites of the domestic animals and of the smaller 

 mammals. Some are of considerable size, and have the integument 

 strongly chitinized, especially along the lateral borders. 



Haematopinus suis, L. (Plate LXVIII, fig. 3). Head elongated, 

 longer than broad ; on each side in front of the antennae seven hairs, 

 and two pairs of hairs near the proboscis. Basal joint of the antenna 

 shorter than the others, which are equal in length. Six fine hairs, more 

 or less marginal, on the frons. Thorax straight at its junction with 

 the abdomen ; mesothoracic stigma with a large white peritreme ; a very 

 small prothoracic stigma present ; the posterior angles form large conical 

 projections ; a single very distinct median plate on the sternum, broader 

 than long and broadest in front, with its anterior angles produced, the 

 posterior angles projecting to a less .extent ; a very small stigma in 

 each anterior angle. The sternal plate is wanting in young specimens ; 

 it may be asymmetrical, one of the anterior angles with its stigma being 

 detached. Abdomen without lateral swellings in the adult ; borders 

 festooned on account of the projections which bear the stigmata of 

 the second to seventh segments. On the dorsal surface of each segment 

 a brown transverse band, which occupies the middle third of the length ; 

 each median band is often formed by two consecutive bands ; external- 

 ly on each side, between the band and the stigmal plate, a small clear 

 brown, slightly chitinized projection. In the male the last segment 

 is not narrowed at the sides ; the ventral genital plate is large, 1 mm. long 

 by *6 mm. broad, and the genital apparatus, seen through it, passes 

 beyond it in front to a distance of '7 mm. Under the plate there is 

 a membrane set with spines which serves as a sheath for the apparatus. 



This is the type of the genus Haematopinus, Leach, and is the largest 

 species of the genus. It is found on the domestic pig and on the 

 wild boar in most parts of the world. In spite of its size it is not 

 suitable for the study of the anatomy, as the extremely tough nature 

 of the integument, which can hardly be cut with a dissecting needle, 

 renders it extremely difficult to dissect. 



The lice found on domestic pigs of Asiatic origin, and on the wild 

 boar of Asia, differ slightly from those of Europe, and are regarded 

 by Neumann as a subspecies, under the name H. suis adventicus. The 



