PSOROPriC MANGE — SHEEP SCAB. 



617 



when the mites are two-thirds the size of the adults ; when seven to 

 eight days old the mites are matm*e and riBady to pair ; several (three 





/ , 





or four) days are allowed for pairing ; another generation of eggs 

 may be laid fourteen to fifteen days after the laying of the first gene- 

 ration of eggs. Without going into all of the other observations on 



