154 



SCIENCE 



[N. S. Vol. XXXVII. No. 943 



of trained clivers from European Eussia, and 

 the prospects for a satisfactory yield of pearls 

 are considered to be good.* 



Geo. F. Kunz 



SPECIAL ABTICLES 



THE DOCOPHORI OF THE OWLS 



Exactly a dozen species of Docophorus 

 (genus of Mallophagan parasites) have been 

 described from the owls (Strigidw). I think 

 the number is about double what it ought to 

 be. The species center about three well- 

 known and well-differentiated types, repre- 

 sented by the long-established species, D. ros- 

 tratus Nitzsch, D. cursor Nitzsch and D. 

 ceblelrachys Nitzsch. The name of Nitzsch 

 means that these three species were described 

 about a hundred years ago and were based on 

 specimens derived from European birds. All 

 of these species have since been taken from 

 North American owls, as well as from owl 

 hosts from other parts of the world. 



The three species differ markedly from each 

 other in various characters, the most quickly 

 recognizable of which are the shape and mark- 

 ings of the head. In rostratus the clypeal 

 portion of the head is drawn out and narrow 

 in front, in cursor it is shorter and broader, 

 and in ceUehrachys it is still shorter and 

 broader, so that the head is a sort of broad, 

 solid, bull's head. The species might well 

 have been named taurocephalus, a name used 

 later by me for another Docophorus. 



Of the nine other so-called species of owl 

 Docophori three have been described from 

 American specimens, viz., D. syrnii by Pack- 

 ard from Strix varia varia from Ohio; D. 

 hulonis by Osborn from Bulo virginianus 

 from Pennsylvania, and D. speotyti, ■ also by 

 Osborn, from Speotyto cunicularia hypogwa 

 from Nebraska and Colorado. D. syrnii Pack- 

 ard is unrecognizable. It does not count. 

 Professor Osborn's two species do count, of 

 course. They belong to the cursor type of owl 

 Docophori and are very partial, indeed, to 

 this type, for they imitate their European 



'Report of Consul John F. Jewell, of Vladivo- 

 stok. 



model pretty closely. However, Professor Os- 

 born's specimens are different from Nitzsch's. 

 But that is a conspicuous thing about the 

 Mallophaga. The individuals of the same 

 species, when they are taken from different host 

 individuals, reveal easily perceived differences. 

 It is a condition that comes about, probably, 

 through the unusual isolation of the separate 

 groups of individuals that compose the spe- 

 cies. Each group, which is at bottom a fam- 

 ily group, and represents a family strain, is 

 more or less effectively marooned on an ani- 

 mated island, which is the body of its indi- 

 vidual bird host. And hence the variations 

 of each family strain are preserved and ac- 

 cented by the necessary inbreeding due to this 

 isolation. 



Thus while Professor Osborn's cursor-like 

 species are different, they are not very dif- 

 ferent, and the same is true of several other 

 species of owl Docophori representing not only 

 the cursor type but the cehlehrachys and the 

 rostratus type. 



I have just received from Professor Cock- 

 erell several specimens of Docophorus from 

 Asio flammea (collected at Boulder, Colorado) 

 and in attempting to determine them I am 

 interested to discover that if I follow tradi- 

 tion I shall have to add another species of 

 Docophorus to the list for the owls, which 

 would make the thirteenth! This makes me 

 hesitate. What I believe ought to be done is 

 to let these new specimens unite some friendly 

 but now separated species, instead of compel- 

 ling them to make the situation more intoler- 

 able. For to recognize thirteen species of one 

 Mallophagan genus from thirteen species of 

 owls — ^f or that happens to be the exact number 

 of owl species from which Docophori have 

 been taken — and four of them from a single 

 owl kind, would be unnatural, and also most 

 inviting of ill luck ! I am sure of the unnat- 

 uralness from my knowledge of the host dis- 

 tribution of the Mallophaga. The trouble is 

 that the isolation of the Docophorus (and 

 other Mallophagan) individuals on owls is 

 even more effective than on most other birds, 

 for owls are peculiarly non-gregarious and 



