33 



THE 'WHITE-MARKED TUSSOCK MOTH. 



Orgyia leiicostigma, S. & A. 



The most common of the caterpillars found on city shade trees is 

 that of the white-marked tussock or vaporer moth. It is pre-emi- 

 nently a shade tree pest, rarely found in gardens and yet more rarely 

 on trees away from cities and towns. In New York and Philadelphia 

 it is the troublesome pest on streets and in the 

 city parks. As we get into smaller towns and 

 villages the pest becontes even less, until finally, 

 in the country, it disappears almost altogether. 



This caterpillar is recognizable by its bright 

 red head and by the velvety black back, on which 

 there are four thick t^^f ts of creamy colored hair, 

 looking like round paint brushes. At either 

 end is a pair of long, black, plume-like hair 

 pencils and there are shorter tufts of hair along 

 the sides. In general, the caterpillars give the 

 impression of being yellow, with black and 

 bright red markings. They are first noticed in 

 May, on practically all kinds of deciduous shade 

 trees. When suddenly disturbed they drop, 

 suspending themselves by silken threads at- 

 tached to the leaves from which they started. 

 They become full grown toward the end of June and then begin to 

 wander, leaving the trees upon which they have fed, crawling to others 

 some distance away, or along fences to gate posts, tree boxes or to any 

 sort of shelter where, in some angle, they spin a loose, dirty, gray 

 cocoon. The caterpillar has only a small supply of silk and with this 

 it mixes hair from its own body, so as to make a more complete cover- 

 ing. In this cocoon the change to the pupa takes place and in about 

 two weeks adults appear. The male has two pairs of dusty, gray 

 wings, the anterior crossed by narrow, black lines and with a more or 

 less prominent white spot toward the lower outer angle, the posterior 

 without markings. The feelers or antennae are broadly feathered and 

 plume-like, while, when at rest, the tufted forelegs are extended 

 straight forward. The expanded wings measure rather more than an 

 inch from tip to tip. 



Fig. 18 



Caterpillar of the tussock 

 moth. 



