66 INJURIOUS AND USEFUL INSECTS 



feelers are pectinate (comb-like) in the male, serrate in the 

 female ; the proboscis is reduced to a vestige. The moths 

 are sluggish, and remain motionless throughout the day on 

 the trunks of trees, escaping notice by their resemblance to 

 the silvery bark on which they rest. They appear in July. 

 The female lays her eggs in the cracks of the bark, near 

 the ground, and sometimes on the roots of the tree. 



The fresh-hatched larvaa at first gnaw only the bark and 

 young wood ; but after the first winter they bore deep, and 

 run long galleries through the wood in a more or less vertical 

 direction. Though the young larvse are always low on the 

 tree, the older ones may be found up to the height of a 

 man above the ground. The larger galleries are wide enough 

 to admit a lead-pencil, or even a finger. The caterpillars 

 feed only on sound wood, and usually attack trunks of good 

 size, at least as thick as a man's arm. Exposed and solitary 



Fig. 49. — Larva of goat-moth. 



trees are more often infested than trees growing together 

 in a wood or plantation, and the outermost trees of a wood 

 are selected in preference to the rest. The larvse do not 

 feed in winter, but lay themselves up near the bark. They 

 feed for two years before pupating, resembling wire -worms 

 and cockchafers in their prolonged larval stage. It has 

 often been remarked that complete protection and a sure 

 supply of food tend to protract the duration of the larva. 

 A diet of fresh leaves, and more than all, of animal food, 

 tends to abbreviate the larval stage. Full-fed larvae are 

 about 80 mm. long (3 inches) ; the males, however, being 

 shorter. There is a black head, a pair of dark shields 

 on the segment next behind the head, and a single large 

 shield on each of the following segments. The body narrows 

 behind, and is almost free from hair. Young larvae are pink, 

 like boiled shrimps; but the colour darkens with age to a 

 reddish brown, and the shields at length turn almost black. 

 The presence of these caterpillars in a tree is indicated by 



