EARTH-MASON CATERPILLARS. 201 



and care. When one of the latter is dug up, it 

 has the appearance of nothing more than a small 

 clod of earth, of a roundish or oblong shape, but, 

 generally, by no means uniform. The interior, how- 

 ever, when it is laid open, always exhibits a cavity, 

 smooth, polished, and regular, in which the cocoon, or 

 the chrysalis lies secure. (Fig. p. 202, b). The polish 

 of the interior is precisely such as might be given to soft 

 earth by moistening and kneading it with great care. 

 But beside this, it is usually lined with a tapestry of 

 silk, more or less thick, though this cannot always 

 be discovered without the aid of a magnifying glass. 

 This species of caterpillars, as soon as they have 

 completed their growth, go into the earth, scoop 

 out, as the cossus does in wood, a hollow cell of an 

 oblong form, and line it with pellets of earth, from 

 the size of a grain of sand to that of a pea — united, 

 by silk or gluten, into a fabric more or less compact, 

 according to the species, but all of them fitted for 

 protecting the inhabitant, during its winter sleep, 

 against cold and moisture. 



Outside Vitnv of Nests of Earth-mason Caterpillars- 

 One of the examples of this occurs in the ghost- 

 moth (Hepialus humuli), which, before it retires into 

 the earth, feeds upon the roots of the hop or the 

 burdock. Like other insects which construct cells 

 under ground, it lines the cemented earthern walls 

 of its cell with a smooth tapestry of silk, as closely 

 woven as the web of the house-spider. 



Inaccurate observers have inferred that these 



