410 PROCEEDINGS OF THE NATIONAL MUSEUINI vol. loe 



described in this paper that were taken from the Formicariidae. In 

 my opinion the}' are much nearer to these two genera than to the 

 genus Rallicola, in which Hopkins and Clay think they should be 

 placed. 



I am not at all reconciled to Miss Claj^'s theory in attempting to 

 trace the origin and relationship of these species for which sufficient 

 proof seems to be wanting. The fact that they resemble superficially 

 many species of Rallicola may verj'- readily be a case of parallel develop- 

 ment of two offshoots from entirely different ancestors. It does not 

 seem logical that two families of birds so far apart S3'stematically as the 

 rails and ant birds could possibly have acquu-ed the same genus of 

 mallophagan parasites, either by direct inheritance or secondary in- 

 festation. If Fvrnaricola contained but one or two species their 

 presence could be accounted for by secondary infestation, but such 

 could scarcely account for a widespread genus on two families of 

 passerine birds as we have in this case. 



I have had in mj- collection for some time a considerable number of 

 Ischnocera from the ant birds but have never been able satisfactorily 

 to allocate them generically. Since it is clearly evident that they 

 form two closely knit entities which cannot be made to fit into any 

 known genera, I have erected two new genera to receive them. 



Formicaphagus, new genus, is the larger of the two new genera, 

 containing 15 species, and is parasitic on many and possibly all 

 genera of the Formicariidae except the genus Formicarius, on which 

 an entirely different insect is found. I have specimens of this larger 

 genus from 9 genera and 16 species and subspecies of ant birds, ranging 

 from the tiny arboreal genus Myrmotherula to the large, terrestrial 

 genus Pittaso7na. 



Formicaricola, new genus, the smaller of the two new genera, is 

 erected for the mallophagan species parasitic on birds of the genus 

 Formicarius. This smaller genus apparently is restricted to Formi- 

 cariu^, since it was taken only on that genus, and no species of the 

 larger genus {Formicaphagus, new genus) has been taken on any 

 Fonnicariiis. The new genus Formicaricola is represented by seven 

 species taken from seven species and subspecies of the avian genus 

 Formicarius, ranging from northern Mexico to Bolivia. 



The two new genera have certain characteristics in common, but 

 differ ver}'- strikingly in others, as will be shown in their characteriza- 

 tions. The species of both genera form remarkably homogenous 

 groups, and no species of either genus has been taken by me on any 

 other family of birds. 



The species of both new genera, while resembling each other closely, 

 are separated easily by a combination of various small characters. 

 The male genitalia are especially useful in this respect, since no two 



