NEW MALLOPHAGA. 55 



from a single bird, and which is always abundantly pres- 

 ent on its host; or the individuals may be few even though 

 the parasite is a constant one, i. c, almost always to be 

 found on any specimen of the host examined. Trinoton 

 luridum of the ducks is a good example of this constant 

 presence in small numbers. There may be more than one 

 species of the same genus of parasites on a single host, as 

 jLipeurus celer and Lij>eurus varius, both numerous on the 

 Fulmars; but usually the different parasites of a host rep- 

 resent different genera, exemplified by the remaining four 

 species of parasites of the Fulmars which belong to four 

 other and different genera. 



Finally, I may append to these desultory remarks con- 

 cerning the distribution of the Mallophaga and the influ- 

 ence on their taxonomy of their peculiar habits of life a 

 list of those bird hosts with their parasites, the examina- 

 tion of which has afforded the data for this paper. In 

 preparing the list I have eliminated all instances of un- 

 doubted "straggling." 



LIST OF HOSTS WITH PARASITES. 



Colymbus nigricollis calif ornicus. Synthliborhampus antiquus. 

 Docophorus lari. Docophorus moutereyi. 



kauseusis. atricolor. 



Menopou tridens var. insolens. Menopou loomisii. 



Uriuator pacificus. Brachyrhampus marmoratus. 

 Docophorus colymbiuus. Docophorus montereyi. 



graviceps. atricolor. 



Oncophorus advena. Uria troile californica. 

 Menopou tridens var. pacificurn. Docophorus calvus. 



Uriuator lurume. Rissa tridactyla pollicaris. 

 Docophorus colymbiuus. Docophorus lari. 



lari. Lams glaucus. 

 graviceps. Docophorus lari. 



Nirmus farallouii. Larus glaucescens. 

 Ceratorhiua monocerata. Docophorus lari. 



Docophorus acutipecLus. Niimus liueolatus. 



Ptychorharupus aleuticus. Colpocephalurn fuuebre. 



Docophorus montereyi. Menopon infrequens. 



Menopou loomisii. 



