236 stanley hirst on parasitic acari. 



Figures in Text. 

 Fig. 1. Otodectes cynotis var. cati, showing distribution of tracheal 



tubes ; {a) portion of tube greatly magnified to 



show striation. 

 ,, 2. Listrophorid mite (undescribed genus occurring on 



Cricetomys gambianus), showing distribution of 



tracheal tubes. 

 „ 3. Posterior abdominal lobes of males of Psoroptes : (a) 



Psowptes communis var. equi ; (&) var. ovis ; (c) var. 



cuniculi ; {d) var. hovis (from Johannesburg, South 



Africa) ; (e) var. caprae (Cape Vincent, West 



Indies) ; (/) var. hovis (from Amarillo, Texas) ; 



(^r) and (i) var. cervinae (Colorado) ; {Ji) Psoroptes 



natalensis Hirst. 



J own, Quekett Microscopical Club, Ser. 2, Vul. XIV., No. 87, Novemher 1921. 



