^n^ 



9 9 



W. H. Pollen 



a. Cuclotogaster sp. from partridge, show- 

 ing primitive type of head 



W. H. Pollen 

 b. Quadraceps sp. from little gull 



W''^< 



It'. H. Pollen 



\V. H. Pollen 



c. Halipeurus sp. wing louse from Manx d. Ricinus sp., from meadow-pipit ( x 23) 



shearwater ( x 271 



PlaU XXIII DIFFERENT TYPES OF FEATHER LICE 



{a. — c. Superfamily Ischnocera; d. Superfamily Amblycera) 



