652 Large Larch Saw- Fly. [dec, 



Eggs deposited ..; ... 31st May to 2nd June. 



Larvae hatched . ... ... 10th June. 



1st moult ... ... ... 13th to 14th June. 



2nd ,, ... , 1 8th June. 



3rd ... ... ... 21st June. 



4th , , 24th June. 



5th ,, 28th June. 



Larvae began to spin cocoons 2nd July. 



These larvae were still alive in their cocoons on the 7th October, which is 



against the occurrence of a second brood, as previously mentioned. 



The following facts may be noted in addition to those detailed 

 by]Packard. The larvae begin to use the posterior end of the 

 body for clinging in the second larval stage. When a little 

 more than half grown, that is, after the third moult, the larvae 

 begin to congregate in masses similar to those formed by the 

 Pine Saw-fly, L. pint ; this fact is important practically as 

 will be shown in discussing the remedial measures. The 

 mature larvae congregate to a certain extent but not so densely 

 as the younger ones. 



Packard states that once shaken off the trees the larvae 

 cannot ascend the trunk, and he consequently recommends 

 jarring the trees as a good remedy. I have very frequently 

 observed the larvae ascending the trunks of trees from which 

 they have been either shaken off or washed off by rain ; they 

 travel slowly but ultimately regain the twigs. 



General description of the Attack and its Effects. — The ages 

 of the larches which are attacked by the saw-fly vary from 

 5 to about 100 years, that is, practically from the youngest 

 to the oldest. Many of the young plantations consisting of 

 larches of six to eight years of age were badly attacked, but the 

 older plantations of trees from twenty to fifty years of age were 

 affected most seriously, and the results of defoliation by the 

 larvae are more apparent on the older trees than on the trees 

 in the young plantations. 



The effect on the trees of the defoliation by the larvae has been 

 a matter of considerable discussion among owners and others, 

 and there appears to be a tendency to minimise the evil which 

 may result from such repeated annual defoliation. In the 

 United States of America, Packard mentions that in certain 

 regions from 10 to 30 per cent, of the trees were destroyed by 

 the larvae. There is now, however, evidence in the Lake 

 District of the fatal effect of repeated defoliation. In the 



