STATES OF INSECTS. 229 



the rose-beetle, Cetonia aurata, &c, prepare themselves a 

 cocoon, composed of earth, pieces of rotten wood, and any 

 substances within their reach; which they fasten together 

 with a glutinous secretion. The same material is employed 

 by others in forming a cocoon wholly of earth; which 

 is sometimes, as that of the stag-beetle, Lucanus Cer- 

 vus, exceedingly hard ; at others, as that of some moths, 

 Noctua ambigiia, &c, so slight as to fall to pieces as soon 

 as touched a . Other cocoons are formed of grains of 

 earth. Reaumur has given a very interesting account of 

 the procedures of a larva in repairing one of these co- 

 coons, from which he had broken off the top when just 

 completed. Without quitting the interior of the walls 

 that remained, it put out its head from the breach, and 

 for more than an hour employed itself in selecting one 

 by one grains of earth, which it conveyed with its mandi- 

 bles and deposited within its case : it next spun all round 

 the opening threads of silk, to which it attached grains 

 of earth taken from the previously-stored heap, uniting 

 them compactly by means of other silken threads. After 

 employing three hours in this laborious process, the in- 

 dustrious little mason had reduced the diameter of the 

 breach to a few lines. Reaumur was very curious to 

 know how it would fill up this orifice, which would no 

 longer admit the protrusion of its head outside the walls, 

 as in its previous operations. He concluded, that while 

 the rest of the cocoon was exteriorly formed of earth, 

 this opening would be merely closed with silk. He was 

 mistaken, however: the artist knew how to vary its 



a Wien. Verz. I possess a cocoon of this kind from New Hol- 

 land, even now quite solid, and retaining its form. No silk appears 

 to have been used in its composition. 



