PINE SAWFLY. 



351 



needle, and 80 to 120 altogether ; she seals up each egg with 

 a frothy secretion. 



The larvae hatch 2 to 3 weeks later, in May and June, and 

 those of the second brood in August and September. They 

 frequently moult, the empty skins hanging on the needles. 

 The second brood hibernate in cocoons under moss, or on 

 stems or twigs. There is not, however, always a second 

 brood, and the larvae of the first brood may then hibernate. 

 Pupation takes place at the beginning of July * in a compact 

 brown cocoon, among the needles, or in bark-cracks on the 

 stems of the pine. The 

 second brood pupate in 

 March or April in cocoons 

 under moss at the foot of 

 the tree they have attacked. 



The saivflies of the first 

 brood appear at the end of 

 July or early in August, 

 about 2 to 3 weeks after 

 pupation. The insect when 

 ready for flight cuts a cir- 

 cular lid off the cocoon. 

 If an ichneumon fly should 

 emerge instead of the saw- 

 fly, a little hole appears at 

 the end of the cocoon (O) 

 instead of the lid. The 

 second brood usually emerge in 'April, but sometimes not till 

 July, when the sawflies of the two broods become intermingled. 



Generation double, but frequently lasting over a year. In 

 rare cases it has lasted for 2 to 3 years. The insect is very 

 common on the continent of Europe and in the British Isles. 



The naked larvae are susceptible to cold and wet weather. 



c. Relations to Forest. 



The larvae attack the Scots pine, and prefer sickly poles 

 where the leaf-canopy has been interrupted, 20 to 30 years 



* Theodor Hartig states that cocoons spun under moss are dull brown, and 

 those on the tree silky ash-grey, dirty white, or yellowish. Even clean white 

 and rusty red cocoons may occur. 



Fig. 181. Pine-needles, with larvae and 

 cocoon of L. pini, L. 



