﻿FIELD AND FOREST. 55 



which it pushed itself forward. Pupa measured four-tenths inches. 



The following is a description of the moth, which measured ^ inch 

 in the expanse of the fore wings: — "Fore wings grayish white, faintly 

 marked with pale ashy undulating lines, the fore-margin with about 16 

 small oblique dashes, the tip of the wings black with a small square 

 black spot and with a large conical ashy spot near the outer angle, 

 having its edges and middle marked with black lines, the apical mar- 

 gin varied with grey, leaden, and white colors, and a double row of 

 minute black dots ; the hinder wings brown, the head and collar red- 

 dish brown, and the palpi, outwardly and inwardly whitish." 



The eggs of this insect are doubtless deposited upon the seed envel- 

 ope, when young, and the larvae hatching, eat their way in, in the 

 same manner as Bruchus pisi or the "pea-bug." 



Mr. Riley, in the Transactions of the St. Louis Academy of 

 Science, mentions having received these Mexican jumping seeds, 

 which are derived from a plant called arrow weed, ox yerba de flecha, 

 and Colliguaja by the Mexicans,* from San Diego, California. He 

 gives an interesting account of them, substantially the same as that 

 given above, except that the seed is lined inside with a delicate car- 

 pet of silk, and when cut partially open the worm immediately sets to 

 work to mend the break with the same substance. He also states 

 that the worm, before changing, eats a hole through the hard shell, 

 plugging it up with silk ; a slight cocoon is then spun, with a passage 

 leading to the hole. The worm occupies but one sixth the space of 

 the shell, consequently the slightest motion causes the shell to move 

 about. "The jerking motion is conveyed by the worm holding fast 

 to the silk lining with anal, and four hind abdominal pro-legs, which 

 have very strong hooks, and then drawing back the head and fore- 

 body and tapping the walls with the head, often at the rate of twice in 

 a second." 



In Science Gossip, November 1867, we find a communication from 

 Ventnor, Isle of Wight, in which the writer describes the "jumping 

 seed" as a "small excrescence," which had been taken from a haw- 

 thorn ; it was about the sixth of an inch in length, pear-shaped, and 

 in size resembled a grape or raisin stone. The specimen had been 



* Mr. Westwood, infers from subsequent information received that the seeds are 

 in fact Peruvian, having been carried to Mexico, where the plant producing them is 

 called Colliguaja. Those experimented with were received from the neighborhood 

 of Tepic. 



