3 18 
Psyche 
[September-December 
Figures i and 2 show the general appearance of male and female 
adults. The insect is grass green in color at all developmental stages 
and there is a quite distinct sexual dimorphism in the general shape 
of the resting adult. The dimorphism largely derives from a differ- 
ence in the shape of the tegmina. Both sexes have large, widely 
spaced and projecting compound eyes, as have most predatory katy- 
dids. The tibiae of the anterior legs have rows of strongly developed 
spines with which the animal holds and restrains live prey (see 
Figure i). As far as we were able to determine the insect has no 
specialized cryptic or mimetic posture (unlike some of the other tet- 
tigoniids at Wau; see Robinson, 1973). 
We originally considered the possibility that the species was preda- 
tory after an examination of its morphology. Later we found an 
adult male eating a large jumping spider that was obviously not car- 
rion. This was the only instance we saw of predation in natural 
conditions (we never saw the species eating plant material at any 
stage). In captivity the insect caught and ate a variety of living 
insects and was particularly adept at catching calliphorid flies. These 
were caught if they settled close to the resting katydid ; we did not 
see any stalking behavior. The katydid made a rapid forward lunge 
and then trapped the flies against the substrate beneath the spinous 
anterior tibiae. We saw nothing that was homologous to a mantid 
(or reduviid) strike, i.e., the anterior legs were not extended and 
then rapidly folded around the prey in a pincer grip. Figure 1 
shows a male Hexacentrus feeding on an acridiid nymph which was 
caught after it had been left (by us) in a damaged condition in 
front of the katydid. 
Figure 3. Sonagram of interrupted stridulation. Frequency range 0-16 
KHz. Time base 0.6 seconds. 
