200 
Psyche 
[September 
12. Cathartus advena (Waltl.) At Palos on October 6, 
1928. Possibly a chance occurrence or had pene- 
trated the colony for hibernation. 
Elateridae 
13. Melanotus communis (Gyll.) A single adult which was 
still very soft and pale from pupation, taken from 
a nest at Palatine on August 6, 1929. 
Scarabseidse 
14. Phyllophaga species. Larvae, pupae and imagos taken 
from the Palos nests on October 6, 1928. Rather 
abundant. 
15. P. horni Smith. One male. In lower dome galleries as 
above. 
On October 6, 1928, thirteen Leptinus testaceus Mull, 
were taken from the upper galleries of a weak colony of 
Formica ulkei Emery. The mound was beginning to be 
overgrown with grasses and measured only eight inches 
high and some two feet in diameter. With the leptinids 
were taken fifty-six Batrisodes and twenty Tachyura. 
Since testaceus is exceptional in the mounds of ants and 
is not reported from those of ulkei , it was sought repeatedly 
but others were not seen. The original lot was carried to 
the laboratory with other myrmecocoles for study, and the 
following points were learned as to the ecology of these 
species : 
Enemies 
Leptinus testaceus Miill. was isolated in a petri dish nest 
and thirteen workers, both major and minor, of Formica 
ulkei were introduced. This group was maintained for six 
days, the ants being fed on sugar water. During this time 
the beetles were not molested by the worker ants. The 
latter passed near or over the leptinids frequently without 
being visibly stimulated beyond a momentary pause in their 
walk, or an occasional investigatory movement of their 
antennae. 
