114 



WORK AT HOME AND IN THE FIELD 



very doubtful whether the damp atmosphere resulting from this 

 inelosure is not injurious to the larvae. It certainly does not seem 

 to have much influence on some, but the unhealthy conditions that 

 result must be detrimental to the inmates. It must also be remem- 

 bered that many species require a dry soil in which to burrow 

 when about to change. 



When the time comes for the change of food, great care must be 

 taken not to injure young and small larvae. In many cases they 

 need never be touched, for if a fresh twig be placed beside the stale 

 one, they will readily find their way to it ; and to facilitate this, and 

 also to afford a convenient foothold to those larvae that accidentally 

 fall from the twig, the layer of sand at the bottom of the bottle 

 should be covered with moss or cocoa-nut fibre. 



If you find it necessary to 

 move the larvae yourself from 

 the stale food, never touch 



FIG. 57. A LARVA GLASS. 



FIG. 58. A LARVA GLASS. 



them with your fingers, but lift them gently by means of a small 

 camel-hair brush. Larger larvae need never be moved at all. They 

 will always search out fresh food for themselves, and the stale may 

 be removed after they have quitted it. 



For rearing larger species ordinary bottles are hardly satisfactory, 

 and we must either use large jars or construct cages of some kind. 



An ordinary bell jar such as is used for covering ferns or for 

 aquaria makes a very useful ' larva glass.' Place a small bottle of 

 water at the bottom, and then introduce sufficient dry clean sand or 

 sifted soil to reach up to its neck. On the top of this place a layer 

 of moss or cocoa-nut fibre. Next introduce the food plant, fixing it 

 firmly in the bottle of water, and plugging up the space between 



