1953] 
Brown — I ndo- Australian Strumigenys 
161 
mens in nature and in the artificial nest in a certain pro- 
portion of individuals in most colonies at any given time. 
Its structure is vaguely granular, and appears to be too 
amorphous to represent a vegetable growth. It is highly 
resistant to organic solvents, and even to strong acids and 
bases up to the point where these begin to attack the in- 
tegument itself. It can sometimes be loosened in water, 
but does not show appreciable reduction after prolonged 
soaking. It appears most likely to be a direct secretion of 
a largely proteinaceous nature. Similar-appearing incrusta- 
tions are frequent in the myrmicine tribes Basicerotini and 
Attini, though phylogenetic relationships between these and 
the Dacetini {Strumigenys, etc.) do not appear to be very 
close. Most species showing the secretion in the Basicero- 
tini and Dacetini show other structural and behavioral con- 
vergences, and are, generally speaking, members of the 
microgenton of Silvestri. The dacetines feed chiefly upon 
certain collembolan families, and it is possible that this 
secreted crust has something to do with the predatory habit. 
Among undescribed Strumigenys from the New World 
tropics, I have seen other forms with secretory lacunae, 
though placed differently to those of the doriae group and 
probably developed convergently. 
It is unfortunate that each of the three species treated 
below is known only from the unique type, a situation 
which makes taxonomic conclusions somewhat uncertain. 
The characters given to separate the three are, however, 
of a degree of distinctness equal to those seen in related 
Strumigenys species known from considerably more satis- 
factory samples. Emery’s brief and somewhat questionable 
diagnosis with figure of S. doriae remains to be checked 
and amplified by some future specialist having access to 
the type. 
The measurements and their abbreviations are those I 
have used in various works on the dacetine ants: tl, total 
length, or sum of lengths of the various tagmata, including 
the closed mandibles; hl, maximum measurable length of 
head in dorsal view, including all of clypeus and occipital 
lobes; ml, distance to which the closed mandibles project 
beyond the clypeal margin, measured while head is in same 
position as for hl measurement; WL, diagonal length of ali- 
