1957] 
Brown — Orectognathus and Arnoldidris 
21 
cipital lobes are more abundant and larger, more nearly 
foveoliform. The second female paratype has the propo- 
deal spines very slightly arched as seen in side view, but 
still straighter than in any of the workers. 
Wilson found the first workers (No. 839) foraging on 
bushes or small trees under 2 m. tall, at about noon on 
a sunny day, but in deep shade in rain forest. Careful 
search of the ground litter below the bushes turned up 
two dealate females and additional workers, indicating 
that the nest was inadvertently scattered. The workers 
are very slow and deliberate in their movements, and 
often stand still in one spot for long periods. One worker 
was seen walking with gaster recurved under the ali- 
trunk. None was seen with prey, which could have been 
one of the numerous Collembola seen so commonly on 
stems and leaves of trees where the ants were taken. 
In a colony fragment returned to the United States alive, 
the female and four workers were exceedingly sluggish, 
and failed entirely to attack some entomobryid collem- 
bolans enclosed in a small nest with them in such a way 
that numerous contacts between springtails and ants were 
enforced. One egg was laid by the ants, but this disap- 
peared within a few days. The colony appeared to be 
disorganized, and the adults spent much of their time 
resting on the glass cover forming the ceiling to their 
chamber. After two or three weeks, all adults had died. 
A single worker labeled “Wisselmeren : Obano,” col- 
lected at 1770 m. in Netherlands New Guinea by J. L. 
Gressitt, is slightly larger than the szentivanyi type 
series: tl 5.8, hl 1.44, hw 1.30 (Cl 90), ml 0.83 (mi 58), 
wl 1.73 mm., but is similar in form. Its color is darker: 
head and alitrunk blackish-piceous ; nodes and alitrunk 
orange or deep ferruginous yellow; legs and antennae 
ferruginous yellow, mandibles straw yellow. Punctation 
of head more distinct throughout, especially over the entire 
dorsal surfaces of occipital lobes, which are covered with 
spaced, umbilicate foveolae. Whether this specimen belongs 
to szentivanyi and is merely a geographical variant can 
only be decided by the study of more material. 
