1930 ] Two Mermither gates of Ectatomma 51 
feebler and the surface, therefore, even smoother and more 
shining. 
The punctigerum mermithergate (Fig. ld,e) was cap- 
tured by Mr. Darlington on April 20, 1920 at St. Augustine, 
Trinidad, together with three normal workers of the vari- 
ety. Were it not for this association the specific identity of 
the parasitized specimen might be doubtful, though its 
cephalic and thoracic sculpture is clearly of the E. tuber- 
culatum type. The specimen measures 16.6 mm. in length 
and is longer than the average normal worker which meas- 
ures only about 10-12.5 mm., but the proportions of the 
head, thorax and abdomen are very different. In the mer- 
mithergate the head measures only 3.2 mm. in length, in- 
cluding the mandibles, the thorax 4 mm., the abdomen 9.4 
mm. The corresponding measurements of the normal large 
worker are: head 3.5 mm., thorax 4.5 mm., abdomen 4.5 
mm. Though the head and thorax resemble those of the 
normal worker they are therefore decidedly smaller and 
more slender. The head, excluding the mandibles, is nearly 
square, very slightly longer than broad, with very feebly 
rounded sides and the posterior angles merely rounded-rec- 
tangular and not sharply rectangular or even distinctly 
cornuate as in the normal worker. Eyes larger, more pro- 
tuberant, nearly hemispherical. There are no traces of 
ocelli. Antennal scapes extending nearly half their length 
beyond the posterior corners of the head (only two-fifths 
in the normal worker), mandibles somewhat narrower. Be- 
sides its smaller and more slender dimensions the thorax 
differs from that of the normal worker in having the lateral 
tubercles of the pronotum more acute and less auriculate, 
the median tubercle or projection narrower and more 
sharply defined. The base and declivity of the epinotum 
form a less distinct obtuse angle and the epinotal teeth are 
reduced to mere denticles. Petiole very similar to that of 
the normal worker but the node slightly more compressed 
anteroposteriorly. Postpetiole and gaster much larger and 
more voluminous, owing to their containing a large Mer- 
mis, the compact coils of which are visible through the dis- 
tended intersegmental membranes. The hypertrophy af- 
fects not only the postpetiole and first gastric segment but 
also the deflected second, third and fourth gastric segments, 
