INTERNAL THICKENED RIDGES 



LABRUM. 



HEAD ^ 



ANTENNA-- 



EYE ' 



^. OCULAR SETA-'' 



THORAX < 



ABDOMEN •{ 



Plate XXI 



SUTURE 



-MANDIBLES 

 LABIUM 8c 



"maxillae 



CLAWS 



SETAE 



J. G. Bradbury 



Head feather louse, Saemundssonia sp., from common tern, showing important 



characters ( x 46) 



