32 Trans. Acad. Sci. of St. Louis. 



uses which have been developed consist, of either a high 

 specialization of the front pairs of legs into chitinous 

 claspers shown on PL V, Fig. 19, in the development of 

 the maxillary lip so as to form two curved, shovellike 

 claspers, or in the special modification of the hind group 

 of legs into clasping structures. A careful examination 

 of these clasping organs shows that they can only be used 

 upon a hair of almost a definite diameter and even of a 

 definite shape. A hair much larger than those of the 

 accustomed host would frequently be too large even to 

 permit the presentation of the claspers, while a hair 

 much smaller could not be held tightly at all. 



A List of the Analgesidae Fou^^d upon Moee thax One 

 Host Species, Togethee with the Names or Their 



HOSTS.^*^ 



Pteeolicheae. 



freyana Haller. 



F. gracilipes Trt. & Megn. — Grus antigone (L.), Ephippiorhynchus seae- 



galensis (G. Shaw). 

 F. pelargica Trt. & Megn. — Clconla ciconla (L.), C. nigra (L.), Euxe- 



nura maguarl (Gm.). 

 F. cnserina Trt. & Megn. — Anser anser (L.), Cygnus olor (Gm.), Chen 



hyperboreus (Pall.). 

 F. anatina (C. L. Koch) — Anas acuta L., A. crecca L., A. querquedula 



L., Mergus serrator L., Fullgula fuligula 

 (L.), Nettapus auritus (Bodd.). Other 

 water birds. 

 F. leclerci Trt. — Loblvanellus senegalus (L.), L. Indlcus (Bodd.). 

 F. caput-medusae Trt, — Sula bassana (L.), and other species of the 



genus. 

 F. gigas Trt. — Diomedea nlgrlpes Audub., and on related species. 



pteeolichus Robin. 



p. lunulatus (Haller) — On species of Strlgidae. 



P. dcnticulatus M4gn. & Trt. — Pyrrhula cruentata (Wied), and Amer- 

 ican parrots. 

 P. canestrinii Trt. — Ara macao (L.), A. canga, A. severa (L.). 



^'' The following list has been compiled chiefly from Canestrini's mono- 

 graph of tlie family published in 1899. Des Tierreich, Lieferung 7. 



