EXPLANATION OF PLATE XVII. 
Process of feeding larva in bast under glass. 
(a) Larva one day old in bast of Picea excelsa. 
(b) Full-fed larva in bast of Larix europea. 
(c) Immediately prior to 4th moult. 
(d) Immediately after 4th moult. 
Nat. size. 
