1979] 
Taylor — Ant Genus Aulacopone 
359 
of the scapes, as is so generously accommodated in Proceratium and 
Discothyrea. Immediately behind this section the carina is laterally 
expanded and partly reflexed, to form an obtuse lobe, which appears 
to partially lock the scape into position when the antennae are folded 
(Arnoldi, Fig. 3). These modifications cause the frons and posterior 
parts of the clypeus to form a regularly convex, more-or-less triangu¬ 
lar shield-like face to the cranium, a configuration not unlike that of 
other small cryptobiotic ants, such as some in the myrmicine tribes 
Dacetini and Basicerotini. The fronto-clypeal structure of Aulaco¬ 
pone is unlike that of any other ponerine ant, and thus immediately 
diagnoses the genus. The extent to which it might be associated with 
specialised trophic behaviour, like egg-feeding, is quite unknown. In 
addition the petiolar node (Figs. 3, 4), though relatively broad, is 
structured similarly to those of some Discothyrea females, and is 
quite unlike those of any Heteroponera species. The structure is 
somewhat like that typical of the primitive ponerine tribe Amblyopo- 
nini, and might represent a holdover from a remote amblyoponine 
ancestry. Abdominal segment IV is somewhat reflexed (Arnoldi, Fig. 
1), though less strongly so than in Proceratium, Bradoponera or 
Discothyrea; or even some Heteroponera species (notably H. leae 
(Wheeler), in which segment IV is more strongly reflexed than in A. 
relicta and relatively short compared to segment III). Other descrip¬ 
tive details are covered by Arnoldi and illustrated in Figs. 1-4. 
Several points deserve further discussion. (1) The eyes are notably 
hairy (Figs. 1, 2). This might not be the case in workers. However, the 
only similar condition I have seen in tribe Ectatommini is that of a 
worker of an undescribed species of Heteroponera (aff. H. leae) from 
southwestern Western Australia. No other Australian Heteroponera 
has hairy eyes. (2) The scanning electron microscope has revealed an 
unusual structure on each pronotal humerus of the subject specimen, 
positioned as shown in Fig. 3. One of these structures is illustrated in 
detail in the stereoscopic pair of micrographs comprising Fig. 5. Each 
consists of a small shallow depression, without pilosity, enclosing 
several irregular troughs which each contain a number of minute 
pores. These are presumably the ducts of some previously unreported 
prothoracic gland. A detailed survey by steroscopic light microscope 
has revealed no comparable structure in any other of the several 
hundred ectatommine species, of all known genera, represented in the 
Australian National Insect Collection. 
