V0 'iS^ VI J Kellogg, Some Parasites of Birds. 233 



strong biting and masticatory mandibles. The order includes 

 four families, comprising 21 genera. Of these, two families, 

 represented each by a single genus, and including altogether not 

 more than 50 species, are restricted to mammals, while the other 

 two families with their numerous genera are found on birds 

 alone. 



To ornithologists the Mallophaga will have no special interest 

 except as parasites of birds. That is, their peculiarities of struct- 

 ure or of development, or their systematic isolation among in- 

 sects will be of but secondary interest compared to the facts of 

 their parasitic relations to their hosts, the birds. And, indeed 

 they are those facts about the Mallophaga which are, perhaps, of 

 first importance to entomologists. For it is because of their 

 parasitic habits that they have come to depart widely from their 

 racial type. 



I shall endeavor, then, to state briefly some of the ascertained 

 facts regarding the relations of the Mallophaga to their hosts, and 

 to indicate certain interesting moot points, to whose settlement 

 the aid of ornithologists needs to be invoked. 



Nearly one thousand species of Mallophaga have been 

 described by three or four European entomologists from Euro- 

 pean and Asiatic birds. In this country 262 species of Mal- 

 lophaga have been recorded from 257 species of North American 

 birds. Of these species 105 have been determined to be identi- 

 cal with species previously described from birds of Europe or 

 other foreign country, while the remaining 157 have been 

 described as new species. An important problem is immediately 

 before us : how come Mallophagan species to be common to 

 foreign and to American hosts ? First, must be eliminated those 

 hosts common to the two continents either by reason of circum- 

 polar range or importation. Then must be eliminated the few 

 possible cases of the meeting on mid-ocean islands of related 

 maritime birds of strong flight from the two continents. Finally 

 there remains a large number of instances in which a Mallopha- 

 gan species is common to American and foreign hosts of distinct 

 species, and distinct genera frequently, who have no possible 

 chance for that contact which might allow the parasites to 

 migrate directly from one host to the other. This problem of 



