A four-winged insect resembling a butterfly but differing from the latter in that its feelers usually are feathery and not terminated by distinct knobs. When at rest the moth’s wings are not held erect, as is often the case with butterflies. Instead, they are either folded back flat over the insect’s body or held flat at its sides. Also, moths are generally nocturnal. The insect referred to in Scripture is evidently the clothes moth, particularly in its destructive larval stage. (Job 13:28; Ps. 39:11; Isa. 50:9; 51:8; Hos. 5:12; Matt. 6:19, 20; Luke 12:33; Jas. 5:2) The ease with which a moth can be crushed was a figure employed by Eliphaz with reference to the frailty of mortal man.—Job 4:17, 19, 20.
Female clothes moths lay their eggs on woolen or silk fabrics, or furs, distributing them so that emerging caterpillars will have ample room and material on which to feed. The caterpillars will not eat until they have first protected themselves with a “house” or case constructed from the available fibers. In this “house” they remain as they feed.—Job 27:18.
Commenting on the building procedure followed by a clothes moth caterpillar that was placed on a desk covered with a cloth, James Rennie, in his book Insect Architecture, pages 192, 193, writes: “It did not cut a single hair till it selected one for the foundation of its intended structure. This it cut very near the cloth, in order, we suppose, to have it as long as possible; and placed it on a line with its body. It then immediately cut another, and placing it parallel to the first, bound both together with a few threads of its own silk. The same process was repeated with other hairs, till the little creature had made a fabric of some thickness, and this it went on to extend till it was large enough to cover its body; . . . We remarked that it made choice of longer hairs for the outside than for the parts of the interior, which it thought necessary to strengthen by fresh additions; but the chamber was ultimately finished by a fine and closely-woven tapestry of silk.”