854 PROTECTION AGAINST INSECTS. 



larvae come down to hibernate. The pigs will not eat the 

 cocoons, which are too tough for their taste, but crush them 

 in numbers. 



iv. Planks smeared with tar may be put up to catch the 

 sawflies, the tarred sides being turned towards the sun, and 

 the tar renewed from time to time. 



v. Mixture of quicklime with the litter and then watering it. 

 The heat thus engendered kills the larvae and pupae that are 

 in the litter, and preserves the latter for the forest. This 

 remedy was tried with success on 6 acres of 12 15 Scots 

 pine plantation with heather undergrowth, and cost 12s. 

 an acre. 



vi. If no other remedy should be found effective, the 

 damaged wood must be cut down, and the roots grubbed up 

 late in the summer or winter ; branches may be spread on the 

 soil and burned before grubbing up the roots, and one or 

 two field-crops harvested before the land be restocked with 

 pines. 



Several other species of Lophyrus of generally similar habits 

 also attack Scots pine. Miss Ormerod* states that much 

 injury was done in 1890 to three or four thousand acres of 

 young Scots pine in Argyleshire by L. rujus, Klug, the larvae 

 of which are dull greenish-grey, with black heads. The flies 

 appeared in August only, and the ? are reddish and the $ 

 black ; both sexes have red legs. 



Plants 2 to 6 feet high were more subject to attack than 

 older ones. In Germany the sawflies appear in May, and the 

 larvae May July, to attack trees of all ages, but to prefer those 

 10 to 15 years old, and one-year-old needles. It attacks the 

 Austrian as well as the Scots pine, and appears to have 

 a single generation. It is not so common as L. pini, and 

 should be treated similarly. 



The larvae of various species of Nematus (with 14 prolegs) 

 and Lyda (2 prolegs) also attack spruce, larch, and pines. 

 N. ericksoni, Hrtg., has been very destructive to young larch 

 in Cumberland in 1906. Its larvae may be recognised by 

 their grey colour, with a darker medium zone. N. laricis, t 

 Hrtg., also attacks larch ; its larvae are green. 



* Op, cit., page 255, 



