This section is from the book "The Gardener's Monthly And Horticulturist V20", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
Mr. Riley exhibited certain seeds which possessed a hidden power of jumping and moving about on the table. He stated that he had recently received them from Mr. G."W. Barnes, of San Diego, Cal., and that they were generally known by the name of Mexican Jumping Seeds. They are probably derived from a tricoccous euphorbiaceous plant. Each of the seeds measures about one-third of an inch, and have two flat sides, meeting at an obtuse angle, and a third broader, convex side, with a medial carina. If cut open, each is found to contain a single fat, whitish worm, which has eaten all the contents of the seed and lined the shell with a delicate carpet of silk. The worm very closely resembles the common Apple Worm (Carpocapsa po-monella , and, indeed, is very closely related, the insect being known to science as Carpocapsa sal-titans. It was first recorded by Westwood in the Proceedings of the Ashmolean Society of Oxford, in 1857 (t. 3, pp. 137-8), and repeatedly referred to under the name of Carpocasap Dehai-siana in the Annales of the French Entomological Society for 1859. The egg of the moth is doubtless laid on the young pod which contains the three angular seeds, and the worm gnaws into the succulent seed, which, in after growth, closes up the minute hole of entrance, just as in the case of the common Pea Weevil (Bruchus pisi). Toward the month of February the larva eats a circular hole through the hard shell of its habitation, and then closes it again with a little plug of silk so admirably adjusted that the future moth, which will have no jaws to cut with, may escape from its prison.
A slight cocoon is then spun within the seed, with a passage-way leading to the circular door; and the hitherto restless larva assumes the quiescent pupa state. Shortly afterwards, the pupa works to the door, pushes it open, and the little moth escapes. When ripe, the shell is very light, and, as the worm occupies but about one-sixth the enclosed space, the slightest motion will cause the seed to rock from one of the flat sides to the other. But the seed is often made to jerk and jump, and, though this has been denied by many authors, Mr. Riley had had abundant proof of the fact, and had seen the seed jerked several lines forward at a bound, and raised a line or more from the surface on which it rested. If the seed be cut, the worm will soon cover up the hole with a transparent membrane of silk; and if two of the opposite angles be cut, the movements of the worm can then be seen, if the seed be held against the light. It then be-comes evident that the jerking motion is conveyed by the worm holding fast to the silken lining by its anal and four hind abdominal pro-legs, which have very strong hooks, and then drawing back the forebody, and tapping the wall of its cell with the head, sometimes thrown from side to side, but more often brought directly down as in the motion of a wood-pecker's head when tapping for insects.
In drawing back the forebody the thoracic part swells, and the horny thoracic legs are withdrawn so as to assist the jaws in receiving the shock of the tap, which is very vigorous, and often given at the rate of two a second, and for twenty or more times without interruption. It is remarkable that this, of all the numerous seed-inhabiting Lepidopterous larvae, should possess so curious a habit. The seed will move for several months, because, as with most Tortricidous larvae, this one remains a long time in the larva state after coming to its growth and before pupating.
Mr. Barnes gives the following account of the plant, received through Capt. Polhamus, of Yuma, A. T. It seems to be called both Yerba de flecha and Colliguaja by the Mexicans: