AN ASYMMETRICAL BIRD-LOUSE FOUND ON THREE 

 DIFFERENT SPECIES OF TROUPIALS. 



By John Howard Paixe, 



Of ihc Bureau of Entomology, United States Department of Agriculture. 



In a paper on the possible relation of the Mallophaga to bird phy- 

 logeny, Harrison (1914) mentions and figures the heads of three 

 asymmetrical species of bird-lice, Lipenrus quadrimacidatus Piaget. 

 L. asymmctricus Piagot, and Degeeriella asyinmetrka Nitzsch, con- 

 sidering them congeneric, inasmuch as all three are from related 

 hosts, all Struthiones. 



The writer, however, has recently come into possession of several 

 specimens of both sexes of an asymmetrical form taken from skins of 

 three closely related Icterids, collected by the Smithsonian Biological 

 Survey of the Panama Canal Zone in 1911 and 1912 — viz, Waglers 

 Oropendola, Zarynchus vmgleri (Cana, E. Panama, Feb. 12, 1912), 

 and two Caciques, Cacicus microrhynchus (Rio Indio, Canal Zone, 

 Feb. 8, 1911) and Ostinops decumanus { = Cassiciis cristatns in 

 Giebel and Piaget) (Bosca de Cupe, June 19, 1912). The speciniens 

 of ^lallophaga have been deposited in the collection of the United 

 States National Museum. 



This peculiar species (pi. 32, fig. a) is Giebel's Philopeterus 

 aTTibiguus^ the asymmetrical character of which has passed unnoticed 

 since its description, an oversight probably explained by the fact that 

 this most striking feature is completely omitted in Giebel's figures, 

 though accurately described in the text (Giebel, 1847). Piaget 

 (1880), in redescribing the species, of which he saw no material, 

 makes no mention of its asymmetry. Giebel's specimens were from 

 Cassicus cnstatus, which corresponds specifically with one of the 

 writer's host records. 



Carriker (1903) has described a species from Zanjnchus wagleri 

 under the name of Nirmus francisci, which corresponds in host 

 species and in all characters to P. amhifjims, except that no mention 

 of asymmetry is made. It is described, however, as having an emar- 

 ginate clypeus and is doubtless a synonym. 



The type of asymmetry exhibited in P. ambiguus is similar to that 

 in Degeeriella asymvietrica^ consisting of a rather deep clypeal 

 emargination, appearing symmetrical in the very youngest stages, 



Proceedings U. s. National Museum. Vol. 63-220 1. 



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