REVISION OF THE GENERA GNOSTUS AND FA BRA SI A 
(COLEOPTERA: PTINIDAE) 
By John F. Lawrence 1 and Hans Reichardt 2 
The species of Gnostus and Fabrasia are the only myrmecophilous 
Ptinidae occurring in the New World, although the family is rep- 
resented in South Africa and Australasia by at least 12 genera of 
inquiJines. Gnostus comprises three species ranging from Bolivia 
and central Brazil to Florida and the Bahamas and all apparently 
associated with ants of the genus Crematogaster. The three species 
of Fabrasia are all South American, and two of these (described 
below) have been taken with ants of the genus Camponotus. 
Gnostus jormicicola was described by Westwood (1855) from 
material collected with ants in Brazil. Although the species bore a 
distinct resemblance to the Paussidae in the structure of the legs, 
antennae, and prothorax, Westwood concluded, after a thorough 
comparative study, that it was “most nearly allied to such of the 
Xylophaga of Latreille as possess five-jointed tarsi . . Later au- 
thors were more impressed by the specialized features of the species, 
and it was placed in a distinct family by Gemminger and Harold 
(1868). Wasmann (1894) and others placed it near the Paussidae, 
Pselaphidae, Scydmaenidae, or Ectrephidae. Gnostus remained a 
genus of dubious affinities until Forbes (1926) pointed out the 
similarities in wing venation and wing-folding pattern to members 
of the family Ptinidae. In the present study, it was found that the 
male genitalia of G. jormicicola and G. floridanus Blatchley (Figs. 
13-14) are of the same general type as that of Fabrasia , Ftinus, 
Pseudeurostus , Gibbium , and several of the Old World Ectrephinae 
(Hinton, 1941; Sharp and Muir, 1912). The ectrephines have al- 
ready been placed in the Ptinidae by Wasmann (1916) and will 
be treated in a forthcoming paper (in preparation). 
The genus Fabia was proposed by Martinez and Viana (1964) 
for a Brazilian species (F. alvarengai) , but no mention was made 
of myrmecophilous habits in the species; the name was later changed 
to Fabrasia (Martinez and Viana, 1965) because of homonymy. 
Last year we found specimens of a second species of Fabrasia among 
the William Morton Wheeler inquiline collection in the Museum 
of Comparative Zoology, and shortly after this Father Thomas Borg- 
Aluseum of Comparative Zoology, Harvard University, Cambridge, Mass. 
2 Departamento de Zoologia, Secretaria da Agricultura, Sao Paulo, Brazil. 
Manuscript received by the editor January 6 , 1966 
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