DAMAGE CAUSED BY ANIMALS. 185 



rain during the time of swarming often kill off a good many of 

 the little moths. 



The Larch-bark Tortrix, Grapholitha Zebeana, may also be 

 mentioned. The little caterpillars live in the cambium and in 

 the outer layer of the sapwood of small stems and branches of 

 young Larch, on the bark of which they form conspicuous blisters 

 and excrescences. 



III. OTHER INJURIOUS INSECTS. 



A. SAW-FLIES (Tenthredinidw). 



88. The Pine Saw-fly, Tenthredo (Lophyrus) pini. 



(Vide Plate IV. fig. 26.) 



The wings of the female fly have a span of 0'64 to 0*72 inches. 

 Its feelers are short and delicately toothed ; its head is black in 

 colour, whilst the body is yellowish with black patches on the back, 

 and with three black rings or sections on the abdomen. The male 

 insect is essentially smaller, but has beautifully double-feathered 

 antennae, and is of a darker colour generally, with yellowish legs. 



The tailed-caterpillars, which have 22' legs, are of a dirty 

 yellowish-green colour with a brown head, and black markings 

 over the abdominal feet ; when touched, they suddenly rear or 

 raise their heads like a sphynx, or in a cobra-like manner. 



In the chrysalis all the parts of the fully-developed saw-fly 

 are already recognisable. It passes the pupal state in a leathern 

 cocoon, mostly of a dark-brown colour, formed in the fissures of 

 the bark, on the needles of the tree, or on the ground under moss. 

 When effecting its exit from the cocoon as imago, this saw-fly 

 makes a characteristic circular section. 



The Pine saw-fly has a double generation. During the latter 

 part of April and the beginning of May the first swarming takes 

 place, when the female lays 120 or more eggs on the edges of the 

 spines, which it wounds for the purpose with a saw-like ovi- 

 depositor, whence it derives its English name. From 10 to 20 

 eggs are deposited inside each needle, and then the wound is closed 

 up with a kind of frothy slime. 



The larvae or caterpillars make their appearance in May and 

 June, and hang in clusters on the whorls of young Scots Pine, 

 especially of those near the edge of compartments, or on such 



