PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 633 



roll from oue side to another, but actually move by jerks and jumps, 

 and will, when very active, jump at least a liue from any object tliey 



Carpocapsa SALTiTANS : rt, larva; ft, pupa; c, imago — enlarged, bair-lines showing 

 uat. size; d, front wing of a pale var. ; e, seed, uat. size, with empty pupa skin; /, 

 do. showing hole of exit. — (After Ri'ey.) 



may be resting on. The actual jumping power has been doubted by 

 some writers, but I have often witnessed it. To the uninitiated these 

 movements of a hard seed seem little less than miraculous. They are 

 induced by a plump, whitish, lepidopterous larva which occupies about 

 one-fifth of the interior, the occnpied seed being, in fact, but ahollow shell, 

 with an inner lining of silk which the larva has spun. The larva looks 

 very much like the common api)le-worm {Carpocapsa pomonella), and be- 

 longs, in fact, to the same genus. It resembles it further in remaining for 

 a long time in the full-grown larva state before transforming, so that the 

 seeds will keep up their motion throughout most of the winter months. 

 When about to transform, which is usually in the months of January 

 and February, it cuts a neat, circular door in the convex side of its house, 

 strengthens the same with silk, spins a loose tube of silk within the 

 seed, and therein transforms to the pupa state. The moth soon after- 

 ward pushes its way out from the little door prepared for it. 



The moth was first described in 1857 as Carpocapsa saltitans by Prof. 

 J. O. Westwood,* and afterward as Carpocapsa dehaisiana by Mous. H. 

 Lucas, t 



In regard to the plant on which these seeds occur there is much yet 

 to learn, and I quote what Mr. G. W. Barnes, president of the San 

 Diego Society of Natural History, wrote me in 1874 concerning it, in the 

 hope that some of the botanists present may recognize it: 



"Arrow-weed {Yerba cleflecha). — This is the name the shrub bears 

 that produces the triangular seeds that during six or eight months have 

 a continual jumping movement. The shrub is small, from 4 to G feet in 

 height, branchy, and in the months of June and July yields the seeds, 

 a pod containing three to five seeds. These seeds have each a little 

 worm inside. The leaf of the plant is very similar to that of the ga- 



*Proc. Ashmolean Soc. of Oxford, 1857, t, 3, pp. 137-8; see also Trans. Lond. Ent. 

 Soc., ser. 2, 1858, t. IV, p. 27, 'and Gard. Chron. 1859, Nov. 12, p. 909. 



+ "Note sur les grains d'uue Euphorbiac^e de Mexique sautant an dessus du sol par 

 les vibrations d'nne larve de I'ordre des lepidopteres vivant en dedans."— (Ann. Soc. 

 Ent de France, ser. 3, t. 6, Bull. p. 10, p. 33, p. 41, p. 44, 1859; t. 7, p. 561-566.) 



