1930 ] Tivo Mermither gates of Ectatomma 49 
the first, enlarged and distended with Mermis. Legs de- 
cidedly longer than in the normal worker. 
Head sculpture peculiar in that the longitudinal rugae are 
finer, closer together and decidedly more numerous on the 
front than in the normal worker. The reticulate rugae on 
the sides of the vertex in the latter are also replaced by 
such longitudinal rugae. Thoracic sculpture as in the nor- 
mal worker. Petiolar node transversely rugulose and not 
irregularly rugose above. Postpetiole and gaster more 
opaque throughout, finely and densely striate, with a satiny 
lustre ; the striae transverse and converging behind on the 
postpetiole, longitudinal on the gastric segments. Venter 
more shining but very finely and transversely, though more 
superficially striate throughout. The sculpture of the ab- 
domen therefore resembles that of the normal worker 
tuberculatum. The pilosity of the *mermithergate is quite 
normal. 
Although the typical form of E. tuberculatum is a com- 
mon ant over a large portion of the Neotropical Region 
from Southern Mexico to Southern Brazil, its two varie- 
ties, acrista, Forel and punctigerum Emery have a much 
more restricted distribution. The var. acrista is known 
only from Paraguay; Emery (1890 b) described punc- 
tigerum from a couple of workers taken by Simon at San 
Esteban, Venezuela. It is certainly the common, if not the 
only form of the species in Trinidad, where it has been 
taken by Prof. R. Thaxter and myself, and Dr. George Salt 
and Mr. Darlington brought me specimens of it from 
Northern Colombia. The worker differs from that of the 
typical tuberculatum in coloration, being decidedly darker 
and more brownish, and in the sculpture of the postpetiole 
and first gastric segment, the coarse, sparse punctures on 
which are larger, more impressed and interrupt the striated 
sculpture. Moreover, the striation on the first gastric seg- 
ment is much feebler than in the typical tuberculatum and 
becomes obsolete on the sides, so that the whole segment is 
decidedly smoother and more shining. The female punc- 
tigerum (undescribed) is scarcely paler than the worker, 
with very similar abdominal sculpture though in some spec- 
imens the striation on the first gastric segment is even 
