28 NORTH AMERICAN ANOPLURA 



long hairs near the posterior margin. Forcipes of the penis on each side 

 with a large, heavily chitinized tooth. Spiracles very small. Anterior 

 legs more slender and smaller than the others. Tibiae and tarsi as in 

 Linognathus. 



The genus was established for two species, H.lyriocephalus (Denny) 

 and H. ventricosus (Denny), both occurring upon European species of 

 hares and rabbits. Enderlein did not have specimens of H. ventricosus, 

 and it has since been pointed out that in this species the pleural plates 

 are really present, altho they are extremely small. Because of this it 

 has been suggested that these two species should not be referred to the 

 same genus. Mr. Cummings, of the British Museum, has very kindly 

 sent us specimens of both species for examination, and we are of the 

 opinion that they should be referred to the same genus, even though the 

 pleural plates are really present in one and absent in the other. These 

 plates are so extremely small in H. ventricosus that the step from "pleu- 

 rites present" to "pleurites lacking" is after all not very great, especially 

 as the two species agree very closely in other particulars. H. lyriocepha- 

 lus may be distinguished from any of the species of Linognathus, in 

 which genus the pleural plates are also lacking, by the extremely broad 

 head and by the very short gonapods of the female. 



There have previously been referred to this genus only the two spe- 

 cies mentioned above. We are provisionally referring to it a third spe- 

 cies, which we are describing as new, taken from a vizcacha (Lagidium 

 peruani) in South America. This last species is certainly very different 

 in many respects from the other two in the genus, yet there seems to be 

 no good reason for establishing a new genus for it, and it cannot well be 

 referred to any other genus as yet established. 



Haemodipsus ventricosus (Denny). 

 Plate II, fig. 2; plate IV, fig. 5; plate V, fig. 12; text fig. n. 



Haematopinus ventricosus Denny, Mon. Anopl. Brit., p. 30, pi. 25, fig. 6, (1842). 

 Haemodipsus ventricosus Enderlein, Zool. Anz., vol. 28, p. 143, (1904). 

 Haematopinus ventricosus Osborn, Bui. 5, n. s., U. S. Dept. Agr., Div. Ent, p. 182, 



(1896). 

 Haemodipsus ventricosus Dalla Torre, Genera Insect., Anoplura, p. 15, (1908). 

 Haematopinus (Polyplax) ventricosus Neumann, Arch, de Parasit, vol. 13, pp. 527- 



528, (1909). 

 Haemodipsus ventricosus Mjoberg, Arkiv. for Zoologi, vol. 6, no. 13, p. 165 (1910). 



Four females from a hare, Lepus calif ornicus (Freestone, Sonoma 

 county, Calif.), and one very badly damaged female from a domestic rab- 



