544 



CALIFORNIA ACADEMY OF SCIENCES. 



Comparing the land birds with the water birds as hosts 

 for Mallophaga, I find that many more individuals among 

 land birds than among water birds are free from parasites, 

 and that among the infested birds the number of indi- 

 viduals of Mallophaga on a single bird individual is much 

 greater among the water bird species than among the 

 land bird species. It is noticeable that the larger land 

 birds such as hawks and grouse show man}^ more para- 

 sites than the smaller birds ; and to some extent the 

 greater abundance of parasites on water birds may be 

 due to their distinctly larger average size as compared 

 with land birds. 



LIST OF HOSTS AND PARASITES. 



Colinus virginanus. 



Lipeurus dissiinilis. 

 Callipepla califoruica. 



Lipeurus docophoroides. 



Goniodes maminillatus. 

 Phasianus nyctheinerus. 



Lipeurus introductus. 



Goniodes cerviuicornis. 



Gouiocotes creber. 



Meuopou nionostcechuni. 

 Coluroba livia. 



Lipeurus baeulus. 



Gouiocotes corupar. 



Menopon longicephalum. 

 Elanus leucurus. 



Colpocephalum osborni. 



Menopon decoratuni. 

 Circus hudsonius. 



Nirmus fuscus. 

 Buteo swainsoni. 



Nirmus fuscus. 

 Archibuteo lagopus sancti-johannis. 



Docophorus taurocephalus. 



Nirmus fuscus. 



Colpocephalum flavescens. 



Haliseetus leucocephalus. 



Nirmus discocepbalus var. 

 blys. 



Colpocephalum flavescens. 

 Bubo virginianus. 



Docophorus cursor. 

 Nyctea nyctea. 



Docophorus ceblebrachys. 

 Strix pratincola. 



Docophorus rostratus. 

 Dryobates pubescens. 



Docophorus evagans. 

 Melanerpes formicivorus bairdi. 



Docophorus californiensis. 

 Colaptes auratus. 



Docophorus alienus. 

 jungens. 

 Chord eiles virginianus henryi. 



Lipeurus macrocephalus. 

 Cha?tura pelagica. 



Nitzschia dubius. 

 Trochilus anna. 



Nirmus eustigmus. 

 Trochilus rufus. 



Nirmus snodgrassi. 



