592 Farmers’ Bulletin 1169. 
Remedies—Winter burning the rubbish and breaking up the 
ground at the base of infested trees should destroy many of the in- 
sects. Where practicable, hand picking of worms or infested leaves 
early in the spring is a great help. Finally, lead arsenate (p. 11) is 
always a reliable stand-by against these insects. 
Fic. 32. 
Large elm and willow sawfly: a, Willow leaves showing location of eggs; b, 
twig showing incisions made by adult; c, egg; d, newly-hatched larva; e, e, mature 
larve ; f, cocoon; g, open cocoon showing pupa; h, pupa, side view; i, mature sawfly ; 
j, k, saw of female; c, d, j, k, much enlarged, the rest less enlarged. (Riley.) 
BARK, WOOD, AND TWIG BORING INSECTS. 
GENERAL. 
Boring insects secure their nourishment either by extracting it from 
chips of bark and wood that they bite off and swallow as they bur- 
