336 DIRECT BENEFITS DERIVED FROM INSECTS. 



bricius a , seems doubtful, though certainly many of them 

 afford a very strong silk, and might be readily propa- 

 gated ; and I have now in my possession some thread more 

 like cotton than silk spun by the larva of a moth, which 

 when I was a very young entomologist I observed (if my 

 memory does not deceive me) upon the Euonymus, and 

 from the twigs of which (not the cocoon) I unwound it. 

 It is even asserted that in Germany a manufacture of 

 silk from the cocoons of the emperor moth (Saturnia 

 Pyri ?) has been established 11 . There seems no question, 

 however, that silk might be advantageously derived from 

 many native silk-worms in America. An account is 

 given in the Philosophical Transactions of one found 

 there, whose cocoon is not only heavier and more pro- 

 ductive of silk than that of the common kind, but is so 

 much stronger that twenty threads will carry an ounce 

 more . Don Luis Nee observed on Psidium pomiferum 

 and pyriferum ovate nests of caterpillars eight inches 

 long, of gray silk, which the inhabitants of Chilpancingo, 

 Tixtala, &c. in America, manufacture into stockings and 

 handkerchiefs 41 . Great numbers of similar nests of a 

 dense tissue, resembling Chinese paper, of a brilliant 

 whiteness, and formed of distinct and separable layers, 

 the interior being the thinnest and extraordinarily trans- 

 parent, were observed by Humboldt in the provinces of 

 Mechoacan and the mountains of Santarosa at a height 

 of 10,500 feet above the level of the sea, upon the Ar- 



a Vorlesungen, 325. 



b Latr. Hist. Nat. xiv. 150. Tljree modern species of Saturnia 

 were formerly considered as varieties only, and distinguished by the 

 trivial name of Pavonia major, media, and minor ; these are now 

 called S. Pyri, Spini, and Carpini. Ochsenh. 



' Pullein in Phil. Trans. 1 759. 54. d Annals of Botany, ii 1 04. 



