820 THE POPULAR SCIENCE MONTHLY, 



by the ants prevent germination, is not invariably successful, but that 

 a small percentage of stored seeds sometimes do begin to germinate. 

 When this was the case, he also observed the highly interesting fact 

 that the ants then knew the most effective method of checking further 

 germination, for he found that in these cases they gnawed off the tip 

 of the sprouting radicle. This fact deserves to be considered as one 

 of the most remarkable among the many remarkable facts of ant 

 psychology. 



Passing on now to the harvesting ants of the IN'ew "World, the in- 

 sects here remove all the herbage above their nest in the form of a 

 perfect circle, or " disk," fifteen to twenty feet in diameter. Every 

 grass or weed within the disk is carefully felled, and, as the nests are 

 situated in thickly-grown localities, the effect of the bald or shaven 

 disk is highly conspicuous and peculiar, exactly resembling in min- 

 iature the " clearings " which are made by settlers in the backwoods. 

 The disk, however, is not merely cleared of herbage, but also carefully 

 leveled all inequalities of the surface being reduced by pellets of soil 

 being built into the hollows to an extent sufficient to make a uniformly 

 flat surface. In the center of the disk is the gateway of the nest. 

 From the disk in various directions there radiate out-roads or avenues, 

 which are cleared and smoothed like the disk. These roads course 

 through the thick grass, branching and narrowing as they go, till they 

 eventually taper away. They are usually four to seven inches wide at 

 their origin, and may be from sixty to three hundred feet in length. 

 Along these roads there is always passing during the daytime a con- 

 stant double stream of ants, one being laden and the other not. 



In their manner of gathering and garnering grain these harvesters 

 resemble in general the harvesters of Europe ; but it is alleged by Dr. 

 Lincecum that in one respect their habits manifest an astonishing, and 

 indeed wellnigh incredible, advance upon those of their European 

 allies. For this observer, who, it must be remembered, was the first 

 to call attention to these ants in the Kew World, and whose other 

 observations, extending over a number of years, have since been fully 

 confirmed this observer states in the most positive terms that the 

 ants actually sow the seeds of a certain plant called the ant-rice, for 

 the purpose of subsequently reaping a harvest of grain ; hence these 

 ants have been called the " agricultural ants." Now, there is no doubt, 

 from the subsequent observations of McCook and others, that the ant- 

 disks do very frequently support this peculiar kind of grass, and that 

 the ants are particularly fond of its seed. Nevertheless, McCook did 

 not himself witness the process of sowing, although he is not disposed 

 to doubt the statements of his predecessor upon the subject. These 

 statements, as already observed, are most emphatic and precise Lin- 

 cecum saying, in italics, that he knows and is certain about the fact ; 

 but until corroborated it is safest to regard the fact as not yet fully 

 established. 



