98 
Psyche 
[June 
Assignment of the name 
Acanthognathus ocellatus was described by Mayr (1887) from a 
single worker taken by Hetschko in “St. Catharina,,” southern Brasil. 
Since that time Acanthognathus has been collected rather frequently 
in southeastern Brasil, and until recently, it was assumed that all 
of these collections belonged to A. ocellatus . This assumption was 
based partly on the fact that the accumulating samples all clearly 
belonged to a single endemic southeastern species, and partly on 
Santschi’s confident determination of 1922, by which he attached 
the name ocellatus to the commonly-collected species and gave a 
crude figure of the worker head over this name. His sample came 
from the vicinity of Rio de Janeiro. 
Borgmeier had early doubts concerning the identity of this form, 
as seen from some labels on specimens in his collection that read, 
(( Acanthognathus sp. nov.” Borgmeier’s opinion must have arisen 
when he compared his specimens of this form with Mayr’s original 
description of A. ocellatus , for the match is a poor one. Mayr gives 
the length of the mandibles in ocellatus as 0.9 mm, and the head 
length as 1.0 mm, which yields a mandibulo-cephalic index (MI) 
of 90, whereas MI in the common species runs from 63 to 73 in 
the sample available. More significant even than this is Mayr’s 
description of the cephalic sculpture of ocellatus as, . . . nicht dicht 
mit sehr grossen , kreisrunden , flachen und sehr seichten Punkten 
besetzt, jeder punkt hat in der Mitte eine sehr kleine kegelige 
Erhohung, welche ein Haar tragt; die Zwischenraume zwischen den 
Punkten , wie auch die Punkte selhst sind glatt und glanzend . . 
The commonly-collected form, on the contrary, has dense, finely rugu- 
lose-punctulate, opaque sculpture within and between the numerous 
small circular fossae over the entire cephalic dorsum behind the eyes. 
It therefore seems clear that the southeastern Brasilian form called 
“A. ocellatus” (at least since 1922) cannot belong to that species, and 
we here describe it as a new species, A . rudis (below). 
The problem remained as to what the original A. ocellatus really 
was. Unfortunately, the unique type specimen is missing from the 
place where one would expect to find it in the Mayr Collection in 
Vienna, and it was presumed lost. In recent years (Kempf, 1964), 
the rare species A. hrevicornis has been found in the state of Rio 
Grande do Sul, neighboring Santa Catarina to the south. This 
species conforms to the ocellatus description in size and cephalic 
sculpture, but the promesonotum of brevicornis is smooth and shining, 
with a few scattered, feeble fossae, whereas Mayr described ocellatus 
as having (f Der ganze Thorax grob und verworren gerunzelt mit 
eingestreuten solchen haartragenden Punkten, wie sie am Kopfe 
