1907.] 
Wheeler, A New^ Guest-ant. 
81 
presence of the brood, however, caused the Leptothorax to react 
by pulHno^ and tweaking- the fore legs and antennae of their 
visitors. By the following day they had brought all their larse 
and pupae together in a single pile on the side of the sponge 
opposite that occupied by the Myrmicas and their brood. 
July 23rd I left Florissant, and for several days traveled about 
in Colorado, carrying the nest in my luggage. The jarring of 
the railway train must have had a tendency to mingle the broods 
of the two species, for during the night of July 23rd to 24th, the 
Leptothorax built a wall of agglutinated sugar crystals about 4 
cm. long, parallel with and about a cm. from the edge of the 
sponge. This wall they were apparently unable to carry up to 
the roof-pane, so that the long, narrow chamber which they had 
endeavored to construct, and in which they had placed their brood, 
was open above and at both ends. The visiting Myrmicas were 
in no wise restrained by the crystalline rampart, but in their 
uncontrollable craving to be near the little inquilines kept climbing 
over it or pushing their way into the openings at the ends. 
No change was observed in the relations of the two species 
till I reached Colorado Springs, July 26th, when I found that the 
Leptothorax had abandoned their useless abode at the edge of the 
sponge and had moved their brood in under a delicate film of 
sugar, which they had built inside the food-cup. This film was 
fastened to the floor and to the vertical wall of the cup, so as to 
enclose a triangular cavity, which communicated with the outside 
by means of a single small opening. Structurally this little cell 
was, of course, an admirable contrivance for preventing the visits 
of the Myrmicas, but, unfortunately, by August ist, its sugar 
wall had been partly dissolved by the moisture in the chamber, 
and partly eaten by the host ants, so that the little guests and their 
brood were again exposed on all sides. They now gave up all 
attempts at keeping their brood sequestered, and by August 3rd, 
when I arrived in New York, to my surprise, both species had 
collected and mingled their broods together in a single large 
cavity in the sponge. Henceforth, till all of the pupse of both 
species had hatched, the workers of one species did not hesitate 
