The Cetonia-larva 



isolate itself in a hammock slung in an open- 

 work enclosure, which enables it to distribute 

 its thread uniformly in all directions. If 

 there be no ceiling, the upper part of the 

 cocoon cannot be fashioned, because the 

 worker lacks the necessary points of sup- 

 port. Under these conditions my Scolia- 

 grubs contrive at most to upholster their 

 little pit with a thick down of reddish silk. 

 Discouraged by futile endeavours, some of 

 them die. It is as if they had been killed 

 by the silk which they omit to disgorge be- 

 cause they are unable to make the right use 

 of it. This, if we were not watchful, would 

 be a very frequent cause of failure in our 

 attempts at artificial rearing. But, once the 

 danger has been perceived, the remedy is 

 simple. I make a ceiling over the cavity by 

 laying a short strip of paper above it. If I 

 want to see how matters are progressing, I 

 bend the strip into a semicircle, into a half- 

 cylinder with open ends. Those who wish 

 to play the breeder for themselves will be 

 able to profit by these little practical details. 

 In twenty-four hours the cocoon is fin- 

 ished; at least, it no longer allows us to see 

 the grub, which is doubtless making the walls 

 of its dwelling still thicker. At first the co- 

 coon Is a vivid red; later it changes to a 

 83 



