20 PROCEEDINGS OF THE NATIONAL MUSEUM Vol. 68 



as broad. Macrochaetae of thorax subeqiial, macrochaeta I equal to 

 about one-half of the width of coxa I; macrochaeta III more than 

 the diameter of thoracic spiracle behind the same. Posterior mar- 

 ginal setae of thorax typically eight on each side, the two nearest the 

 median line and the two nearest the lateral margin of the body much 

 larger than the others. Thoracic spiracles medium sized, diameter 

 of bulb 0.091 mm. Abdomen of typical shape for the genus; setae 

 varying much in size, nearly all of them in transverse rows and but 

 few of them spinelike, or peglike. Pleural plates similar to those of 

 corporis or americanus ; plate I about twice as broad as long. Legs 

 long; femur I twice as long as broad; thumb of tibia I very long, 

 being almost as long as the tibia itself. Chaetotaxy of thumb of tibia 

 I: Chief spine swollen about its middle and attenuated distally, ex- 

 tending beyond the margin by almost exactly one-half its length; 

 anterior accessory spine very slender and situated more on the inner 

 than the anterior margin of the thumb; outer posterior accessory 

 spine a long seta over twice as long as the chief spine; inner poste- 

 rior spine very slender, setiform and situated inside of the anterior 

 accessory spine. 



Length, 3.40 mm.; greatest width, 1.25 mm. 



Type host and type locality. — Japanese race. Type locality (?) 



This description is based upon two males taken at Shuin Gien Su 

 (elevation, 1,200 feet), south of Suifu, Szechuan, China (probably 

 from a Chinaman), May 10, 1924, collected by D. C. Graham. 



The most characteristic thing about this variety (according to 

 characters of two specimens examined) is the small size of the 

 accessory spines on the thumb of tibia I and the rather extreme 

 length of segments II and III of the antennae. This louse prob- 

 ably infests the head chiefly, but to a certain extent the body 

 also. It has not been shown in the case of the yellow race of man- 

 kind or the red race that a distinctive body louse developed apart 

 from the type found on the head. 



Undoubtedly the Chinese race of Pediculus humanus has been 

 brought to America with the influx of Orientals. The nearest 

 approach to an authentic record for this variety from America 

 which the writer has obtained is a lot of 2 females and 1 male 

 taken by Dr. L. Stcjneger (No. 1743) in 1882 from an Aleutian 

 Eskimo at Bering Island. These lice appear to be hybrids. 



PEDICULUS (PEDICULUS) HUMANUS AMERICANUS, new variety 



Plate 3, figs. 9, 10, 11 ; text figs. IB, 2, 3B 



Female. — Head with very poorly developed neck region; fore- 

 head by no means twice as broad as long; postocular tubercle low. 

 Antennae medium in length and not as long as head; segment I 

 almost twice as broad as long; segment II almost one and a half 



