130 THE CANADIAN HOllTICULTURIST< 



HOETICULTUEAL GOSSIP.— XIV. 



BY L. WOOLVERTON, GRIMSBY. 



The Forest Tent Caterpillar, {Clisiocamjoa sylvatica). — A few 

 additional facts about this moth may he interestiug, as it is now 

 foraging among our orchards in such abundance. It belongs to a large 

 family of moths, the Bombycidae, which includes the silk worm and 

 many other beautiful species. The moths of G. sylvatica appear about 

 July 1st, and lay their eggs in clusters of 300 or 400 on the twigs of 

 trees, coated with a gummy substance for protection. The eggs hatch 

 out symultaneously with the development of the young leaves in 

 spring, and immediately begin work. At intervals the worms congre- 

 gate in masses and cast their skins, a fortunate thing for the orchardist, 

 who can destroy them wholesale at such times. 



May 27th I found on nearly every apple tree vast gatherings 

 upon the trunks. I watched one individual moult. A slit was first 

 noticeable on the back just behind the head. A few struggles, and a 

 new head appeared from within the old one, just like it, but of a 

 lighter shade ; a few more struggles, and the whole body was dragged 

 out of its old skin, which had become too narrow to hold its orowino; 

 occupant. Their instinct is remarkable. If three hundred of them 

 are knocked down upon the ground and fall at some distance from the 

 tree, they at once make for the tree again — not one mistakes the 

 direction, but with one accord they crawl towards the trunk. 



Fortunately for us, this caterpillar has several enemies. Besides 

 being subject to disease and frequently to death at moulting times, 

 there are several kinds of parasites of the order Ilymenoptera which 

 prey upon it. The Ichneumon fly, {Physsa Pimpla^ often deposits 

 its eggs beneath the skin of the caterpillar with its long ovipositor. 

 The Pteromalus ClisiocampcB is another great enemy, as its name 

 would indicate. It is probably one of these insect friends that is 

 Bpoken of in the Horticulturist for 1878, p. 19, as saving the orchards 

 in Perth and Middlesex in the year 1877, when the caterpillars were 

 so numerous that fears were entertained that the orchards would be 

 entirely destroyed by them. 



In 1872 we read of the Clisiocampa Sylvatica visiting the country 

 about Montreal in large numbers and completely stripping many trees 



