24 
Psyche 
[ March 
The nine mermithergates (in alcohol), which I designate 
by letters (i being the specimen from Queensland), had the 
following dimensions : 
t 
(a) Length 12 mm.; gaster 6.5 mm. 
(b) Length 14 mm.; gaster 7 mm. 
(c) Length 15 mm.; gaster 6 mm. 
(d) Length 15 mm.; gaster 7 mm. 
(e) Length 15 mm.; gaster 7 mm. 
(f) Length 15.8 mm.; gaster 7.5 mm. 
(g) Length 16 mm.; gaster 6.5 mm. 
(h) Length 16.7 mm.; gaster 8 mm. 
(i) Length 18 mm.; gaster 9 mm. 
With the exception of (c) and (d), all the specimens have 
the gaster so greatly distended with Mermis that the white 
intersegmental membranes are more or less exposed; the 
two exceptions seem to have lost their Nematodes, though 
their gasters are decidedly enlarged. It will be seen that, 
with the exception of (a) and (b), all the specimens are 
longer than the largest normal maxima workers. Yet all 
have the aspect of large minima workers with abnormal 
gastric distension. Closer examination, however, shows 
that they represent a distinct intercaste, in the sense in 
which I used that term in my paper of 1928, because, while 
the head is much like that of the minima, the thorax and 
petiole are clearly of the media and maxima type. The head 
is somewhat broader than in the smallest minimse and in 
several of the specimens less smooth and more sharply sha- 
greened, and all have a faint pit in the place of the anterior 
ocellus. These are characters of the normal maxima. Speci- 
men (i), however, has three very distinct ocellar pits. The 
clypeal carina, well-developed in all the normal worker 
castes, is undeveloped in the mermithergates and reduced 
to a blunt, elongate, median boss as in the normal female. 
The sides of the head are also distinctly less convex than in 
the minima and therefore more like the conditions in the 
female. The thorax is like that of the maxima, being 
stouter through the pronotum, higher and more convex in 
profile, with the epinotum proportionally shorter and more 
rounded, with less distinct base and declivity than in the 
