DIRECT BENEFITS DERIVED FROM INSECTS. 33? 



butus Madrono and other trees. The silk of these nests, 

 which are the work of the social caterpillars of a Bom- 

 byx (B. Madrono\ was an object of commerce even in 

 the time of Montezuma, and the ancient Mexicans pasted 

 together the interior layers, which may be written upon 

 without preparation, to form a white glossy pasteboard. 

 Handkerchiefs are still manufactured of it in the Inten- 

 dency of Oaxaca a . De Azara states that in Paraguay 

 a spider, which is found to near the thirtieth degree of 

 latitude, forms a spherical cocoon (for its eggs) an inch 

 in diameter, of a yellow silk, which the inhabitants spin 

 on account of the permanency of the colour 5 . And ac- 

 cording to M. B. de Lozieres, large quantities of a very 

 beautiful silk, of dazzling whiteness, may be collected 

 from the cocoons even of the Ichneumons that destroy 

 the larvae of some moth in the West Indies which feed 

 upon the indigo and cassada c . 



It is probable, too, that other articles besides silk might 

 be obtained from the larva? which usually produce it, par- 

 ticularly cements and varnishes of different kinds, some 

 hard, others elastic, from their gum and silk reservoirs, 

 from which it is said the Chinese procure a fine varnish, 

 and fabricate what is called by anglers Indian grass d . 

 The diminutive size of the animal will be thought no 

 objection, when we recollect that the very small quantity 



a Political Essay on N. Spain, iii. 59. 



b Voyage dans I'Amcr. Merid. i.212. It may here be observed as 

 a benefit derived by the higher walks of philosophy from insects that 

 astronomers employ the strongest thread of spiders, the one namely 

 that supports the web, for the divisions of the micrometer. By its 

 ductility this thread acquires about a fifth of its ordinary length. 

 Nonv. Diet. d'Hist. Nat. ii. 280. 



c American Phil. Trans, v. 325. 



d Anderson's Recreations in Agriculture t &c. iv. 399. 

 VOL. I. Z 



