Aet. 10 LICE OF THE GENUS PEDICULUS EWING 15 



Zoologfical Park in 1921. Nits were taken from skin (U.S.N.M. 

 200153) of Ateles ater and also from skin of yoimc: male of Ateles 

 ater from Brazil which died in "Washington, July 24, 1915. 



This species is closely related to P. {Parapedlculus) consohrinus 

 Piaget, but differs from Piaget's species in having a much smaller 

 thoracic spiracle, pleural plates smaller, more strongly lobed, and 

 of a different shape (see figs. 3, D and 4, B), particularly is this true 

 of x^leural plates II and V. 



Subgenus PEDICULUS Linnaeus 



In America it is difficult to obtain representatives of man-infest- 

 ing pediculi that are typical of the different forms which originally 

 inhabited the different races of men. This has caused the present 

 writer much inconvenience in revising the genus for the New AVorld, 

 but it may be that as a result of this inconvenience and its attendant 

 ('ela}'^ a much better conception and a much more accurate know- 

 ledge have been obtained in regard to the lice types of mankind. All 

 forms occurring on man are here regarded as varieties of the 

 Linnaean species, PeclicuJus humanus. This is done largely be- 

 cause the writer has been unable to determine just what type of 

 louse is represented by the corporis of De Geer. Undoubtedly many 

 of the body lice of America and Europe are hybrids between the 

 Caucasian head louse of man and some other tj^pe of head or body 

 louse. 



The five varieties of Pediculus humanus which the writer can 

 recognize in our American fauna are keyed out as follows : 



A.* Over one-half of the body setae arranged into definite transverse rows, those 

 that are not so arranged chiefly setiform ; number of setae in ventral row 

 on segment VI of female typically 8 ; diameter of bulb of thoracic 

 spiracle less than a tenth of a millimeter ; macrochaetae of thorax 

 shorter. 



B.' Second and fifth antennal segments each twice as long as broad and 

 segment III broadened distally and distinctly longer than IV. 

 C' Second pair of macrochaetae of thorax longer than the others ; 

 macrochaeta III of thorax situated about the diameter of 

 the thoracic spiracle behind the same 



P. (Pediculus) humanus nigritarum Fabricius. 



P. (Pediculus) humanus corporis De Geer. 



C' Second pair of macrochaetae of thorax subequal with others; 



macrochaeta III of thorax situated more than the diameter 



of thoracic spiracle behind the same 



P. (Pediculus) humanus marginatus Fahrenholz. 



B.' Second and fifth antennal segments each about one and a half times 



as long as broad and segment III subequal or almost subequal 



with I\' P. (Pediculus) humanus americanus, new variety. 



