316 AMERICAN APTERA. 



almost certain by reason of Mr. Snodgrass's care — that these phe- 

 nomena represent truly the normal conditions of distribution. The 

 explanation suggested by me on pp. 458 and 459, Proc. Wash. 

 Acad. Sci., vol. iv, in a discussion of this startling distribution (the 

 occurrence of a parasite species on two hosts so widely systematically 

 separated and with such different habits as a tern and a sparrow) 

 is probably the true one. We have to do, that is with an abnormal 

 j)hase of normal straggling ! On the rocks of the islands maritime 

 and land birds often sit closely huddled (as Snodgrass observed and 

 reported) actual contact of the bodies of the different birds often 

 occurring. Migration of the parasites is thus easily effected, and 

 individuals of a parasitic species nominally peculiar to maritime 

 birds find their way to a sparrow or honey creeper. 



Genus DUCOPHORIIS. 



D. valicliis niinoi* Kell. aud Kuw., Proc. Wash. Acad. Sci., vol. iv, p. 

 460, 1902. 



From Pafjiuus subcdaris (Culpepper, Albemarle Ids.). 



I>. peristictiis Kell. aud Kuw., Proc. Wash. Acad. Sci., v. iv, p. 462, pi. 

 28, fig. 2, 1902. 



From Puffinm subalaris (Culpepper Id.). New record, 



n. tanrocephalus Kell., New Mall. II, p. 471, pi. 45, fig. 1, 1896. 

 From Puffinus subalaris (Seymour Id.), new record. 



D. platycephalus Kell. and Kuw., Proc. Wash. Acad. Sci., vol. 4, p. 461, 

 1>1. 28, fig. 1, 1902. 



From Oceanites gracilis (Wenman Id.). 



D. phiCtonu!ii Osborn, Proc. U. S. Nat. Mus., vol. .xii, p. 189, 1899. 

 From Phcethoii, wtherus, new record (Daphne, Indefatigable Ids."), 

 P. flavirostris, new record (Wenman Id.). 



D. albeiiiarlensii^ Kell. and Kuw., Proc. Wash. Acad. Sci., vol. iv, p. 

 .465, pi. 28, fig. 5, 1902. 



From Plucthon cetherns, new record (Seymour Id.), Sterna J'uligi- 

 noaus (Culpepper Id.). 



I». inelaiiocephalii!i>> Burni., llandb. d. Ent.. vol. ii, p. 426, 1839. 



From Sterna fiiliginosus (1° N. 93° W.), Aaous stolidus (jalapa- 

 qwrisis, new record (Wenman, Culpepper Ids.), Creagras fiircutvs 

 (1° N. 93° W.), new record. 



