THE MOTffS. 46^3 



filk, did we know ho^v to avail ourfelves of their labours, 

 M. de Reaumur has mentioned feveral whofe produftions 

 ought to be fubjefled to experiment by the mauufaclurer ; 

 and in fonrje future period, fome of thefe may be turned 

 to account *. 



Of many of the caterpillars belonging to this clafs of 

 infedls, the filk, it mull be allowed, is altogether unfit for 

 Our purpofes : their coques are not only coarfe, but fo 

 fcantlly provided with filk, that the animal is obliged to 

 join dry leaves, bits of wood, and other materials, in or- 

 der to give liability to its edifice : Farther, many of them 

 fpin under ground, and their work confifts only of join- 

 ing and connefting together, by means of their threads^ 

 different particles of earth, of which their houfe is com- 

 pofed. Thefe caterpillars, when kept by the naturalift, 

 who waits for their phalaenae, muft be fupplied with earth 

 in the boxes in which they are lodged ; otherwife they 

 will perifh, from not being able to conllrud: an edifice fit 

 for their reception f . 



The phalsei.ae, in their chryfalid flate, difFer from the 

 butterflies, in re-.naining for a much longer period before 

 their metamorphofes into perfe6l iiifedls is completed. 

 Their form, too, is then different, being oblong, and not 

 angular, like the chryfalid of the butterfly. Some remain 

 in tiieir coques for feveral years fucceffively ; efpecially 

 if a cold damp fituation has retarded their progrefs. So 

 great is the elfecl of heat in precipitating their develope- 

 ments, that a moth in a warm expofure may be produced 

 from its chryfalid, even in the depth of winter. 



After the phalas'iae ifVae from their lafl covering, fome 

 •f them are deditute of wings : Tliefe are the females of 



certain 



• T»Ele 1. Mem. vi., f Barbut's Oen, InfcdJ. p. 189. 



