4 
Psyche 
[February 
tion of the strange ant, and was not continued long enough to 
seriously damage either contestant. Such attacks usually took 
the form t of pulling legs or antennae, without the usual accom- 
paniment of doubling up the abdomen and rolling about the 
floor of the nest. These data suggest that a colony may break 
up into two or more daughter nests, and that these then grad- 
ually come to react toward each other as strangers. In accor- 
dance with this view is the fact that after the mating season 1 
many of the pure nests have from two to twelve dealated queens ; 
but the number of these seems then to decrease, until by the 
time winged forms are again produced practically no nest has 
more than one old queen. The data of Table 1 must then be 
studied with this evidence in mind, for it is clear that the in- 
dividuals in one nest do not necessarily constitute an entire 
colony, whether we are dealing with pure or with parasitized 
colonies. 
There are two chief problems concerning H. americanus : 
1. How are pure colonies of Leptothorax first infected with 
Harpagoxenus — i. e., what is the method of colony formation? 
2. Does an established Harpagoxenus colony recruit new aux- 
iliaries, and, if so, by what method? 
On July 31 I removed all but some irregular stumps of the 
wings of a queen Harpagoxenus (from nest number 9), and 
placed her in a pure L. curvispinosus nest that contained one 
dealated queen, about 70 workers and brood. The Harpago- 
xenus queen was attracted by the brood, but was quickly at- 
tacked by the workers. She at once became much excited, and 
moved so rapidly that the workers did not succeed in grasping 
her, except occasionally by the stumps of wings. She attacked 
them, but only by “nipping” at the antennae or legs — never did 
she get the “bulldog grip” that is so characteristic of ants — 
even of Harpagoxenus workers. These nips were, however, 
effective, for within half an hour about ten workers had portions 
of one or both antennae amputated. Usually the scape was cut 
in two. The remaining workers in the nest rapidly moved the 
brood as far as possible away from the invading queen — under 
1 Winged forms of L. curvispinosus were found in the nests from July 8 to 
J uly 30, with one belated male on August 10. 
