48 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
gaster is greatly expanded to accommodate the voluminous ovaries. 
On closer examination it is found that in each of the four genera men- 
tioned the female differs from the congeneric worker in certain peculiar 
characters. This will best be seen by a comparison of the worker and 
female Lobopelta with the corresponding phases of Onychomyrmex. 
Many years ago I called attention to the fact that the female Lobo- 
pelta elongata Buckley of Texas has no winged female, but that each 
colony contains a single egg-producing individual, which agrees in 
all respects with the worker, except in the larger size of the abdomen 
and the somewhat more compressed petiolar scale. While at Kuranda 
I .succeeded in finding two females of another species (Leptogenys 
(Lobopelta) fallax Mayr subsp. fortis Forel), a small-eyed form which 
lives, like the species of Onychomyrmex, in red rotten logs in the 
primeval rain-forest. One of these females was the mother of a 
flourishing colony of perhaps 300 workers, the other was isolated in a 
small cavity in a large log and was, therefore, about to start a colony. 
I have figured one of the specimens (Plate 2, fig. 8, 9), with the worker 
(fig. 6, 7) to show the difference between them (in this case greater 
than those obtaining between the female and worker of Lobopelta 
elongata) and between the corresponding phases of Onychomyrmex 
mjcbergi and doddi (Plate 1, fig. 3-6; Plate 2, fig. 3-5). It will be 
seen that in the Lobopelta female the petiole is very much more 
compressed and more curved forward than in the worker, the thorax 
more convex and furnished with a small scutellar sclerite and that the 
head is more orbicular and less rectangular and has distinctly larger 
eyes and a single ocellus. In the female Onychomyrmex the eyes are 
not larger than in the worker, there are no traces of ocelli, the head is 
dilated anteriorly, with rather straight, posteriorly converging sides, 
and with very different mandibles, while the petiole exhibits a peculiar 
modification as compared with that of Lobopelta, being greatly 
swollen behind and much contracted in front. The female Acantho- 
stichus differs from the worker, according to Emery, in its rounded 
head, larger eyes, the presence of three ocellar pits, more widely 
separated frontal carinae, broader thorax, much larger abdomen, the 
absence of prickles on the sides of the pygidium, and a different 
pubescence on the abdomen. The only external differences between 
the female and worker Paranomopone are the presence of a median 
ocellus in the former and a larger postpetiole and gaster. These 
comparisons all point to the conclusion that in each of the four genera 
ergatomorphic females have been developed independently by simpli- 
fication, or atrophy from the primitively winged type of female during 
