OF the SLUG WORM' 7 



that it fhould be placed in contact with the fap-veffels of 

 the leaf, which may. perhaps, in fome fort, contribute to 

 the nourifhment of the embryo larva. If the cuticle of 

 the leaf is carefully raifed, the young larva may be feen, 

 rolled in a fpiral form, as at fig. 1. b. and white ; a flip of 

 a leaf in the vial, with the afhftance of a glafs, will afford 

 you an opportunity to obferve it in this (late. 



Soon after emerging from the blifter a vifcid exuda- 

 tion takes place which covers the whole upper furface of 

 the larva with a flimy coat of an olive colour. In this, 

 as well as in its tardy motion, it refembles the Slug or Snail, 

 whofe name has been applied to it. This coat retains its 

 humidity although expoied to the fierceft heat of the fun: 

 it is probably a defence againft its enemies, and anfwers 

 the further puipofe of fupport when removed from its na- 

 tural pofition. The olive colour in fome is very deep, in 

 others more dilute and inclining to a dirty yellow. 



On firfi quitting the egg the larva is nearly white, the 

 head brown and apparently large in proportion to its 

 body, as in fig. 1. c. where it is delineated both of its 

 natural fize and magnified. — In the courfe of twenty- 

 days it throws off four fkins at nearly equal periods ; it 

 remains in the fifth or laft vifcous fkin fix days, and ac- 

 quires its full growth (fig. 2. a.) ; it then quits this fifth 

 fkin which is left adhering to the leaf (Jig. *. c), and ap- 

 pears in a clean yellow one, entirely free from vifcidity, 

 and has fo different an afpeel that it would not be fup- 

 pofed to be the fame larva (fig. 2. b. iftdjig. 5.) 



After refting fome hours, it proceeds flowiy towards 

 the earth, creeping down the leaf (talk and along the 

 body of the branch — I did not watch its tedious progrefs 

 to the trunk ; but believe, when they arrive at the rough 

 bark, they lofe their foot-hold and fall ; as I have never 

 feen any on the trunk, which mutt be covered With them 

 at the feafon of their defcent if they were able to move 

 on rough furfaces. 



They do not all proceed thus regularly; for I have 

 oblerved, that if the leaf on which they reft, receive the 

 lead mock, they roll themfelves up and fall off. They 



' cuter 



