804 THE AMERICAN NATURALIST. [VoL. XXXV. 
American L. canadensis Provencher,! which I have had occa- 
sion to observe since the second part of this paper was written. 
June 21, I found at Cudahy, near Milwaukee, Wis., two nests 
of this Leptothorax compounded with a large nest of Cremas- 
togaster lineolata Say in an old oak stump. The galleries of 
the Cremastogaster extended far into the dry rotten wood and 
contained numerous worker larvae and pupa. The two Lep- 
tothorax nests, which together scarcely contained more than 
sixty to seventy ants, were about twenty inches apart. Each 
was a simple chamber one-half to three-quarters of an inch in 
diameter excavated in the thick bark, and each communicated 
by means of a slender passage with the subcortical space, 
which was used as a common runway by the workers of 
both species. When the bark was stripped off, several of the 
Leptothorax were seen running on the surface of the wood and 
mingling with the Cremastogasters, which they closely resem- 
bled in coloration and sculpture, though differing in size, 
shape, and movement. The Leptothorax were very timid, and 
when touched with the fingers or tweezers, at once curled up 
and “feigned death,” after the manner of Myrmecina. One of 
the nests contained several mature larvae and pseudonymphs. 
These the workers and the single deálated queen were 
hastily removing to a place of safety. Rain began to fall 
soon after I had opened this interesting compound nest, and 
I was obliged to continue my observations on some living 
specimens of both the species hurriedly confined to a small 
vial. When the two species met, as they often did in these 
narrow quarters, the Cremastogaster stroked the Leptothorax 
with its antenna. On such occasions the latter at once 
crouched motionless and folded its antennz along the sides 
of its head. Then sometimes the Cremastogaster would 
stand over the little ant and lick its rugose head and thorax ; 
at other times it would pass on without bestowing these atten- 
tions on the Leptothorax, which at once sprang to its feet 
and ran away. This performance was repeated so often dur- 
ing the remainder of the day that there could. be no doubt 
1 According to Emery (’94, p. 318) this ant is perhaps only a subspecies of 
the European Z. acervorum. 
