1922] BAILEY—ANT-PLANTS 387 
able extent, except when in search of material with which to 
block up the newly formed entrance aperture. Although von 
THERING is of the opinion that the luxuriant growth of callus is 
due to the stimulus of some substance excreted by the queens, I 
found that homologous structures may be produced by purely 
mechanical injuries. 
With the advent of the first workers, the entrance to the pri- 
mordial chamber is reopened, and the young colony either migrates 
to a higher internode or cuts through the nodal partitions into 
adjoining cavities. Von Inertnc states that the Aztecas always 
abandon the primordial chamber and never perforate its upper and 
lower walls. Such is not invariably the case in C. angulata, for 
primordial chambers were frequently found in direct communica- 
tion with internodes which were not provided with prostomal 
openings. Regardless of its exact mode of origin, the permanent 
domatium soon becomes stocked with food bodies by the young 
workers. These small beadlike structures (fig. 6), which are packed 
with fat and protein, are formed in large numbers in a curious 
cushion or mat of hairs, situated at the base of each petiole. The 
ripe food bodies are so assiduously collected by the ants that it is 
almost impossible to find one in situ, except in young uninhabited 
plants. Indeed, the ants frequently trim away the surrounding 
hairs and dig out the immature food bodies. SCHIMPER interpreted 
these so-called Miillerian corpuscles, and similar structures which 
occur on the leaflets of certain myrmecophytic species of Acacia, 
as metamorphosed glands or highly specialized allurements for 
attracting ants. ReETTIG and others, however, have called atten- 
tion to the fact that such glands occur on plants that are not fre- 
quented by ants, and it is difficult for the adherents of myrmeco- 
phily to account for such occurrences without resorting to the 
purely gratuitous assumption that they are survivals from former 
symbioses. ULE is of the opinion, in addition, that the expenditure 
of carbohydrates and nitrogenous substances, contained in these 
corpuscles, is not compensated for by the protection which the ants 
afford to the plants. 
Although most investigators agree that the food bodies are an 
important item of food in the diet of the Aztecas, it has been 
