Vol. XXvi] ENTOMOLOGICAL \K\VS. Ill 



genual. Tarsal claws of all the legs rather small, and strongly curved. 

 Total length of female, 0.96 mm.; width, 0.70 mm. 



Male. Not found. 



From Ames, Iowa; taken from Mus rattus Linn, by H. E. 

 Ewing. 



An adult female and an immature individual obtained. 

 This species differs from H. americanus Banks in having 

 shorter and much stouter legs, in having larger mouth-parts, 

 etc. The fourth pair of legs in H. americanus Banks ex- 

 tend beyond the tip of the abdomen ; in H. sanguineus n. sp. 

 they fall far short of the tip of the abdomen. 



Fam. DERMANYSSIDAE. 



Liponyssus spiniger n. sp. (Plate IV, Fig. 2.) 



A rather large, dark brown species. Integument well chitinized. 

 Body and appendages well clothed with prominent stout spines. 



Female. Mouth-parts only moderately prominent ; palpi about one- 

 half as long as first pair of legs, with simple segments and no large 

 spines. Chelicerae slender. 



Cephalothorax not demarcated from abdomen, strongly emarginate 

 on its sides, and ending anteriorly in a medium papilla-like process. 

 Dorsally the cephalothorax bears several pairs of very short, stout, 

 slightly curved, sharp spines ; one of these pairs is situated on the 

 anterior papilla-like process, two pairs are situated laterally, and one 

 pair is situated on the antero-lateral margin of the shoulders. Besides 

 these short, stout spines, a longer straight pair is situated on the anterior 

 aspect of the papilla-like process. 



Abdomen about three- fourths as broad as long, broadest above the 

 last pair of legs, and evenly rounded behind. Abdomen clothed with 

 prominent spines ; those on its dorsal surface rather short but sharp, 

 those on the sides of abdomen large, stout, and slightly curved. On 

 the posterior margin of abdomen is situated a single pair of spines, the 

 longest pair found on the body. Anal plate about three-fourths as 

 broad as long, broadest at its base and rounded at its tip; with but 

 a single spine which is located on its posterior margin at the median 

 line. 



Legs stout, the first and second pairs subequal and stouter than 

 the third and fourth pairs. Last pair of le.^s extending to the level of 

 the posterior margin of the abdomen. All the legs well clothed with 

 spines ; the first legs each bear two enormous spines on the dorsal 

 surface of the femur ; the outer is slightly the larger and considerably 

 longer than the segment from which it springs; above the inner at the 



