NEW DATA ON THE HABITS OF 
CAMPONOTUS {MYRMAPHAENUS) ULCEROSUS 
WHEELER 
By William Steel Creighton 
Department of Biology, 
College of the City of New York 
In June 1951 the writer published, in this Journal, an 
account of the habits of C. {M.) ulcerosus. Since that time 
eight more colonies have been observed and additional data 
have been secured on the habits of this remarkable anth 
The truncated head of the major worker of ulcerosus 
has suggested to some myrmecologists a relationship with 
the subgenus Colobopsis. This view is unsatisfactory from 
a structural standpoint, for the two subgenera actually 
have little in common. Nor did it seem likely, since ulcerosus 
is a ground-dweller, that the head of the major could be 
used in phragmosis. It is now certain, however, that the 
major worker of ulcerosus does function as a door and 
does close the nest entrance with the front of the head in 
a fashion essentially similar to the phragmotic major of 
Colobopsis. 
This is possible because ulcerosus constructs a carton 
shield at the nest entrance. In this shield is a single 
aperture which closely approximates, in size and shape, 
the truncated portion of the head of the major. The shield 
is made of a mixture of earth and bits of vegetable detritus. 
The shield is so fragile that it usually cannot be lifted away 
from the nest entrance intact and it is sometimes destroyed 
by a heavy rainstorm. The shield may be flat, dome-shaped 
or tubular. In the dome-shaped and tubular shields the 
length is from ten to fifteen millimeters and the diameter 
from seven to ten millimeters. Since the aperture is notably 
smaller, it forms a bottle-neck which the head of the major 
can close. 
The major of ulcerosus, when acting as a door, lets the 
other members of the colony in and out by backing away 
1 This work was done on a Guggenheim Fellowship for 1951-52. 
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