1944] Genus Pseudomyrma 85 
The color is uniformly testaceous yellow, infuscated at the 
vertex and middle femora. The pilosity is abundant, long and 
erect. The pubescence is long and untidy giving the ant an un- 
kempt appearance. 
Type locality: Guernavaca, Mexico. 
Holotype No. 76, Haskins Collection; 3 paratypes. 
The new species is related to the triplaridis-maligna group 
but differs from the related species by a series of unusual char- 
acters such as the broad node, the head narrowed in front, the 
crenulated epinotal margin. 
Group gracilis. 
Of all the descriptions of forms which undoubtedly belong to 
the gracilis group 15 are good enough to permit the student to 
recognize the form, although even here some descriptions are 
not adequate to decide between two or more. The gracilis group 
shows in miniature the weaknesses of the whole genus Pseudo- 
myrma, namely a planless accumulation of bad descriptions. 
Nobody really knows how many forms of gracilis have actually 
been described, because many of F. Smith’s undecipherable de- 
scriptions may refer to gracilis. 
The confusion arose because an entirely useless character (as 
far as this species is concerned) has been chosen as the chief 
diagnostic character, that is the color pattern. A casual col- 
lector, who picks up a specimen here and there and does not pay 
much attention to the structural features, will come to the con- 
clusion that gracilis is a large group containing many dozens of 
good species; the color patterns are very striking indeed. They 
are however practically worthless, because even individuals 
from the same nest show marked differences. Several of the 
forms which are now recognized as subspecies or varieties in 
good standing exhibit the larger part of the variation range of 
the type series. This is shown in the diagram (PI. IV, Fig. 
26-30). 
All forms of gracilis have at least part of the body black or 
dark brown; on the other hand there is no form which is com- 
pletely black. The original type gracilis (Fabr.) has only the 
mandibles and the petiolar peduncle light colored; the other 
extreme is found in some specimens from the Amazon Valley, 
which have only the head black and the rest of the body yellow. 
The fallacy of basing species, subspecies or varieties of gra - 
