226 
Psyche 
[December 
Springfield, Illinois (April 25) with Lasius americanus; 
Cambridge, Wisconsin (May 26) with Camponotus nove- 
boracensis; Madison, Wisconsin (May 26) with Lasius 
americanus. The species, then, is known to have a num- 
ber of hosts, but is not habitually taken with ants, since 
it is common in moist, decaying log mold in rich forests 
throughout the year. 
The ulkei workers tolerate this pselaphid in their nests, 
seldom giving more than a wave of the antennae when pass- 
ing a beetle. On their part, the beetles usually walk on 
when passing a worker, and seldom crouch to the soil. 
Only once was an ant observed to attack globosus. On this 
occasion the ant picked up the beetle by surrounding it 
with her legs, and then attempted to bite it. The beetle 
however easily escaped, and walked off without the ant 
giving chase. Although rare, such an incident shows that 
the host will attack this normally tolerated form. 
In 1929 the writer was unable to discover what globosus 
fed upon in the ulkei nest. Since then further investiga- 
tion has produced a great deal of information. When glo- 
bosus is isolated in artificial nests with earthworms, the 
beetles feed avidly on the latter, biting the worm’s integu- 
ment and eating the slime secreted. Such feeding, when 
examined under magnification, showed that the pselaphids 
bit and gnawed the worm’s cuticula in the manner of pre- 
daceous carabids and staphylinids. They planted their fore- 
tarsi upon the worm, bit savagely and then pulled upwards, 
bracing their legs against the writhing worm. When en- 
tangled in the slime, the beetles struggled and eventually 
freed themselves, extricating one tarsus after another. 
Wounds made in the worm’s body wall were readily at- 
tacked, as were also amputated segments placed in the 
nests. The twisting worms did not deter their feeding, 
and as many as three pselaphids per square centimeter of 
earthworm surface have been seen feeding, under labora- 
tory conditions. When one pselaphid approaches another 
feeding beetle too closely, the latter pauses long enough to 
bite at the intruder, and usually drives it away. 
The pselaphids may feed for thirty minutes. When 
through eating they clean their antennae and fore-legs as 
noted previously for Megastilicus. After cleaning them- 
