SEX INHKHITANC^K IN rHDICUIJS HUMAXrs 



VAH. coiiroinsK 



Hy KDWARl) IIINDLK, M.A.. Ph.D., 



Charles Kiii«fsl('j/ fA'cturer ami Ihio-Felhuv of Ma(fdideue 



College, Cii mhridye. 



{From the Quick Lahoi'atory, Cambridge.) 

 (With One Chart.) 



The observations on the inheritance of sex in Pediculus hutuanus 

 \'iir,corj)oris, which form the subject of the following pages, were originally 

 commenced in the winter of 1912, when the writer made some (*x|)eri- 

 ments on rearing these panosites in connection with the transmission of 

 certain infections. In the course of these experiments it was observed 

 that, under the same conditions, very unequal numbers of males and 

 females were obtaine<l, and, therefore, individual pairs were isolated and 

 their offspring reared separately. It was then discovered that three 

 kinds of families might be obtained, namely, male, female, or male and 

 female. 



Many series of experiments were begun, but only two of them were 

 carried through more than one generation, as the conditions of rearing 

 were not understood. Eventually one series was carried thn^igh to the 

 second generation, and another one to the fifth, the latter having to be 

 discontinuefi at the outbreak of war. The results obtiiined, therefore, 

 are incomplete, and much work remains to be done on the subject, but 

 as the writer is unable to pursue this line of investigation at present, 

 the records of the exjx'riments are being publishe<l in the hojK' that they 

 may be of assistance to students of the inheritance of sex. 



In my absence Profes.sor Nuttall kindly published a short account of 

 some of the.se experiments in Parasitology (Hiiidle, 1917), but unfor- 



* The expenses of this Investigation were defniyed, in part, by a Grant from the lioyal 

 Society. 



