REPORT OF TEE ENTOMOLOGIST AND BOTANIST. 

 SESSIONAL PAPER No. 16 



205 



Fig 



-The White-marked Tussock-moih 

 caterpillar. 



THE WHITE-MARKED TUSSOCK-MOTH 



IHemerocampa (Orgyia) leucostigma, S. and A.] 



Attacl:— Slender, sparsely hairy caterpillars, from one and a quarter to one 



and a half inches in length, blackish 

 above and paler beneath, with two 

 bright yellow stripes along the back, 

 most conspicuous towards the end 

 of the body. There are four short brush- 

 like tufts of whitish hairs on segments 

 5, 6, 7 and 8. The head chestnut red ; 

 a large patch on segment 2, and two 

 small glandular spots on segments 10 

 and 11, bright vermilion red. From 

 each side of segment 2, close behind the 

 head, are long plume-like tufts of black, barbed and knobbed hairs; a similar pkmie 

 ornaments segment 12. When full grown these catei-piUars have a decidedly hand- 

 some appearance, which is well represented in the accompanying figure. The male 

 ,f , a g [ITS moth measures about an inch and a quarter across the wings, and 

 I fk J5 I is marked as shown in Fig. 22. The colour is gray and the wings 

 are crossed by wavy bands. The base of the fore-wings bears a 

 dark patch, and there is another of smaller size towards the tip. 

 The popular name is given to this moth from the presence of a 

 small white spot near the out^r hind angle of the fore-wings. The 

 female is a large-bodied wingless pale gray creature, with only 

 rudiments of wings. On emerging from the cocoon she crawls on 

 to it and seldom moves from it. After pairing, she lays a mass 

 ''!5" ^rrr^^^y^l^^' ^^ ^SSS, from four to five hundred in number, generally on the 

 outside of her cocoon, and then dies there. These eggs are covered 

 over as laid with a white frothy fluid, which dries over the eggs 

 and protects them through the winter. There is in Canada only 

 one annual brood of this insect. The eggs may be found during 

 the winter on the trunlvs of trees upon which the caterpillars had 

 fed the previous season. The young caterpillars emerge froni the 

 eggs at the end of May or early in June, and soon crawl up and 

 distribute themselves throughout the foliage of the trees, feeding 

 at first beneath the leaves, and when disturbed letting themselves 

 down by a slender silken thread. By the middle of July the eater- 

 Fig. 23.— The wnite- piUars have for the most part become full grown and are preparing 

 marked Tussock- to spin their cocoons. As they increase in size, they become very 

 moth: female moth, ravenous and strip entire trees, eating the cellular tissues between 

 the veins of the horse chestnut leaves, which appears to be the favourite food plant, and 

 producing a characteristic injury, which is easily recognized. These caterpillars have 

 a habit of wandering from branch to branch and from tree to tree, which has given 

 rise to the practice of banding trees with strips of cotton batting. This gives a very 

 untidy appearance to streets and does not do very much good, certainly not enough to 

 atone for the unsightly appearance of the trees. The most effective remedies for the 

 White-marked Tussock-moth are (1) the collection of the conspicuous egg masses from 

 the trunks in winter or before they hatch in spring. This may be easily done by 

 means of a small wire brush on the end of a long pole which will reach up among the 

 larger branches of the trees. Such a brush as this was devised by the late Alderman 

 'Hallam, of Toronto, and used to good effect on the city shade trees during a previous 

 outbreak of this insect. (2) Undoubtedly the best remedy is the systematic spraying 



marked Tussocli- 

 moth : male moth. 



