The way in which these fleet-foots secure their food is highly remarkable, each little theft—which has about it more of the parasite than the brigand—occasioning a group of three. The ants upon which they live are of the species known as _Lasius umbratus_, and, like many other kinds, often feed one another, the hungry asking of the full, by whom he is rarely, if ever, denied. In the process of regurgitation—with which we are now familiar—the two stand fronting each other, with mandibles interlocked, and a drop of honey passes from mouth to mouth. For an instant it trembles between the two, resting on both, and that instant is the opportunity of the _Lepismid_. Darting forward, he interposes his own, and having absorbed some portion of the drop _in transitu_, speeds swiftly away to make a third elsewhere. Such a life, however great may be the thief’s agility, is full of danger, and, from time to time, an individual is captured and killed. In nests under observation such executions may be witnessed, and _Lepismid_ corpses—or, as various professors prefer calling them, _cadavers_—are sometimes noted. Under artificial conditions, however, opportunities of escape are much more limited, unless, indeed, some special provision is made. Thus, when Professor Wheeler first introduced a colony of _Lasius umbratus_ into one of his _formicariums_, he found, after a couple of _dies_,[12] five _Lepismid cadavers_. But having, by the addition to the said _formicarium_ of a _refugium_, or asylum, made it more as _in natura_, this mortality ceased, and the remaining _Lepismids_ continued henceforth _existentes_.