95 



accidentally introduced there some twenty years since by a 

 Mons. Trouvelot, when some larvae he was feeding escaped 

 from his cages. These have since increased to such pro- 

 portions, that they have become a most serious pest. Last 

 year they devastated a very large area ; nearly 500 square 

 miles of territory were much injured by them. The amount 

 of damage caused by these larvae may be gathered from the 

 fact that in 1891, in Massachusetts alone, so alarming was 

 the mischief worked there on fruit and other trees, that a 

 Government Commission was called to try and arrest the evil. 

 They voted the sum of 100,000 dollars for the work ; but even 

 this considerable sum of money was found quite insufficient for 

 the task in hand. They had a force of 117 men, working 

 thirty spraying teams, each carrying a powerful pump and 

 two running lines of hose, mounted with a cyclone nozzle, 

 for diffusing in fine spray a mixture of " Paris green " in 

 water, to poison the caterpillars. But with all this expenditure 

 and force they could only check their ravages, not able to 

 eradicate them. 



Here we see a curious fact, in England this same insect has 

 apparently died out, as it certainly no longer exists with us 

 in a wild state, formerly it was tolerably common in the 

 Whittlesea district and elsewhere. This is a curious problem, 

 why it should die out with us, yet in America increase so rapidly. 

 Another of our English moths, which with us rarely, or never, 

 does any serious mischief, Clisiocampa neustria=^americana, 

 in America commits great injury to fruit-growers, almost vies 

 with O. dispar in its depredations. This species they call 

 the " Tent-worm," or caterpillar, so named from its tent-like 

 nests. Spraying with " Paris green " and " London purple " 

 (two arsenical compounds), is much used in America to destroy 

 this ^arva. It is on authentic record, that a closely allied 

 species, Clisiocampa disstvia, Hulb., occurred in such countless 

 thousands in the larva state, that for three days in succession 

 trains were brought to a standstill, the driving wheels slipped 

 round as though they were oiled. The rails and cross-ties 

 were said to be obscured from sight, and the ground and 

 swamps on each side of the track were covered with millions 



