122 TIMBERS AND THEIR USES 



so, the yeUow-green larvae emerge. Superficially 

 they closely resemble the caterpillars of Butter- 

 flies and Moths ; a closer examination will show 

 that these larvae have more than five pairs of 

 fleshy legs, whereas those of the Butterflies and 

 Moths never have more than five pairs ; again 

 Sawfly larvse have but one pair of eyes. Butterfly 

 and Moth larvse have more. 



There are two broods in a season ; the larvse 

 of the first brood feed upon the leaves of the 

 previous year's growth, those of the second brood 

 feed upon the present year's leaves. Pupation 

 takes place in a little, brown, hard, horny cocoon 

 on the Pine leaf. The larvse of nearly all Saw- 

 flies are gregarious, they live in close association 

 and, as a consequence, they rapidly defoliate 

 the shoots which they favour with their atten- 

 tions. 



A Sawfly which is worthy of mention, on 

 account of the unusual nature of its damage, is 

 Megastigmiis spermotrophos — ^it does not appear 

 to boast of a popular name. The female deposits 

 her eggs in the seeds of the Oregon Pine, a Conifer 

 with a very open cone, and therefore its seeds 

 are easily reached by the female Sawfly. The 

 grubs, which somewhat resemble Weevil grubs, 

 irreparably damage the seeds of this valuable 

 timber tree. The closely related Megastigmus 

 pectinata causes similar damage to the Silver Fir. 



