adhesive and viscid substance, and serve to arrest the wings and legs of the insects that happen to touch the net.”[12] “As the radii,” says Mr. Blackwell (a great authority on British spiders), “are inadhesive, and possess only a moderate share of elasticity, they must consist of a different material from that of the viscid spiral line, which is elastic in an extraordinary degree. Now, the viscidity of this line may be shown to depend entirely upon the globules with which it is studded, for if they be removed by careful application of the finger, a fine glossy filament remains, which is highly elastic, but perfectly inadhesive. As the globules, therefore, and the line on which they are disposed, differ so essentially from each other, and from the radii, it is reasonable to infer that the physical constitution of these several portions of the net must be dissimilar. An estimate,” continues Mr. Blackwell, “of the number of viscid globules distributed on the elastic spiral line, in a net of _Epeira apoclisa_, of a medium size, will convey some idea of the elaborate operations performed by the Epeira in the construction of their snares. The mean distance between two adjacent radii, in a net of this species, is about seven-tenths of an inch; if, therefore, the number seven be multiplied by twenty (the mean number of viscid globules which occur on one-tenth of an inch of the elastic spiral, at the ordinary degree of tension), the product will be 140, the mean number of globules deposited on seven-tenths of an inch of the elastic spiral line. This product, multiplied by twenty-four, the mean number of circumvolutions described by the elastic spiral line, gives 3,360, the mean number of globules contained between two radii; which, multiplied by twenty-six, the mean number of radii, produces 87,360, the total number of viscid globules in a finished net of average dimensions. A large net, fourteen or sixteen inches in diameter, will be found, by a similar calculation, to contain upwards of 120,000 viscid globules, and yet _Epeira apoclisa_ will complete its snare in about forty minutes, if it meet with no interruption.”