984 Distribution of the Large Larch Saw-fly. [march, 



current year's shoots. Such a shoot gives a clue to the 

 presence of the saw-fly, and a further examination of the 

 shoot will reveal the incisions made by the saw-fly's ovipositor 

 on the concave side of the curve. If the eggs have been laid 

 some time they will then appear in the slits as small "eyes " 

 less than T V inch in diameter. The eggs are usually laid 

 alternately in two rows, and as many as 40 may be found 

 in one shoot. Usually the number is smaller, and averages 

 perhaps 20. As the season advances and the caterpillars 

 grow they are more easily detected, and may be readily 

 shaken from the tree when nearly full-grown. Detection of 

 a slight attack is probably easiest in the autumn, when the 

 caterpillar has finished feeding. The curl at the end of the 

 branch is then more pronounced, and the rosettes of needles 

 will have been eaten for a distance of a foot or so from the 

 isolated needles of the current year's shoot, which are not 

 eaten to any extent. This gives a characteristic appearance 

 to the shoot, and, with a little practice, renders detection 

 easy. Confirmation of the presence of the saw-fly may be 

 obtained by searching for the slits in which the eggs are 

 laid at the end of the twigs. Usually also it is possible to 

 find adhering to some of the twigs the moulted skins — as a 

 rule, the black thoracic legs and black head — of the caterpillar. 



The first cocoons were noticed in the Lake District 

 on July 27th, the locality being a particularly warm 

 and sheltered one, while caterpillars were found as 

 late as August 31st in the Welsh District. The 

 saw-fly, as a rule, lays its eggs only in the terminal 

 shoots of the lateral branches. Occasionally, in cases 

 of a bad attack, the leading shoot is attacked, but this 

 is the exception. Where the infestation is of a moderate 

 character, the caterpillars will be found on the lower and 

 central branches of the crown, leaving the upper part prac- 

 tically free. Larvse put into moss as early as the end of July 

 at once commenced to spin cocoons. 



Natural Enemies. — Among the enemies of the saw-fly may 

 be mentioned the vole, rooks, jackdaws, chaffinches, and tits, 

 and the ichneumon-fly, Mesoleius aulicus. At the present 

 time these enemies do not appear to be gaining the upper 

 hand. In certain localities in the Lake District, M. aulicus 



