Pine Sawfly. 



389 



The Pine Sawfly chiefly attacks the Scotch pine, but other 

 species are liable to its invasion. It prefers trees with a sunny 

 aspect, and hence it will be noticed in greatest abundance at the 

 borders of plantations or around clearings. Trees from ten 

 to thirty years old are most subject to the ravages of this pest, 

 but younger and older trees may sometimes be severely attacked. 

 The damage they do is soon noticeable owing to the larvae 

 feeding in companies. These colonies number sometimes as 

 many as a hundred individuals, but as the larvae grow they dis- 

 perse. The damage is chiefly caused by the larvae eating 

 the needles ; this they do in two ways, first by eating notches 

 out of the sides of the needles, and later by eating the 

 whole needles down to their base. There are two broods during 

 the year, the first of which devour the one-year-old needles and 

 the second those of the current year. There are also records 

 of the larvae eating the young bark. 



This forest pest often attacks large areas at the same time. 

 In one instance 2,000 acres were invaded. They often dis- 

 appear suddenly ; this is due to their being so susceptible to 

 climatic changes, cold and wet weather being very prejudicial to 

 them. 



Life History. 



The parent or adult sawfly is nearly three-fifths of an inch 

 across the wings in the male (Fig 1.), and about four-fifths in the 

 female (Fig. 2). The male is black with the apex of the 

 abdomen reddish, with white spots on the underside of the first 

 segment ; in the female the body is dull yellow, with three dark 

 areas on the thorax, and the middle of the abdomen black ; 

 the legs are yellow and the wings have dusky borders, which 

 are not, however, so noticeable in the fore wings of the male. 

 The sexes can most easily be distinguished by the male having 

 doubly pectinate antennae. 



The adults appear usually early in May, and again as a second 

 brood in August. The female, which seldom flies owing to her 

 heavy build, lays her eggs in the needles in slits cut by the saw- 

 like processes common to the sawflies. As many as from ten to 

 twenty may be placed in each needle, but as a rule there are not 

 more than six or seven. It is said that one female may lay 

 as many as 120 eggs. The eggs are usually laid in close 



