ON ENTOMOLOGY. 45 



away the inside. A shelf or plank attacked in this manner, looks solid 

 to the eye, when, if weighed, it will not out-balance two sheets of paste- 

 board of the same dimensions. It sometimes happens, that they carry 

 this operation so far on stakes in the open air, as to render the bark too 

 flexible for their purpose ; when they remedy the defect by plastering 

 the whole stick with a sort of mortar which they make with clay, so that 

 on being struck, the form vanishes, and the artificial covering falls in 

 fragments on the ground. In the woods , when a large tree falls from 

 age or accident, they enter on the side next the ground, and devour it 

 at leisure, till little more than the bark is left ; but in this case, they 

 take no precaution of strengthening the outward defence, but leave it in 

 such a state as to deceive an eye unaccustomed to see trees thus gutted 

 of their insides, and you may as well, says Mr. Smeathman, step on a 

 cloud. It is an extraordinary fact, that when these creatures have 

 formed pipes in the roof of a house, instinct directs them to prevent its 

 fall, which would ensue from their having sapped the posts on which it 

 rests ; but as they gnaw away the wood, they fill up the interstices with 

 clay, tempered to a surprising degree of hardness ; so that when the 

 house is pulled down these posts are transformed from wood to stone. 

 They make the walls of their galleries of the same composition as their 

 nests, varying the materials according to their kind, one species using 

 red clay, another black clay, and the third a woody substance, cemented 

 with gums as a security from the attacks of their enemies, particularly 

 the common Ant, which being defended by a strong horny shell, is more 

 than a match for them, and when it can get at them, rapaciously seizes 

 them and drags them to its nest for food for its young brood. If any 

 accident breaks down part of their walls, they repair the breach with all 

 speed, instinct guides them to perform their office in the creation, by 

 mostly confining their attacks to trees that are beginning to decay, or 

 such timber as has been severed from its root for use, and would decay 

 in time. Vigorous healthy trees do not require to be destroyed, and 

 accordingly these consumers have no taste for them. 



A MASON SPIDER (Mygale Ccementaria) found in the South of 

 France, usually selects for her nest a place bare of grass, sloping in 

 such a manner as to carry off the water, and of a firm soil, without rocks 

 or small stones. She digs a gallery a foot or two in depth, and of a 

 diameter (equal throughout) sufficient to admit of her easily passing. 

 She lines this with a tapestry of silk glued to the walls. The door, 

 which is circular, is constructed of many layers of earth kneaded and 

 bound together with silk. Externally it is flat and rough, corresponding 

 to the earth, around the entrance, for the purpose no doubt of conceal- 

 ment ; on the inside it is convex and tapestried thickly w r ith a web of 

 fine silk. The threads of this door tapestry are prolonged and strongly 

 attached to the upper side of the entrance, forming an excellent hinge, 

 which when pushed open by the Spider shuts again by its own weight, 

 without the aid of spring hinges. When the Spider is at home and her 



