246 OHIO EXPERIMENT STATION: BULLETIN 332 



Nature of work. The insects are leaf eaters and, so far as 

 observed, confine their injuries to this field. During the later 

 stages of their growth they devour all parts of the leaf excepting 

 the midribs and when unusually abundant are responsible to a 

 great extent for the practical defoliation of some species of trees. 

 Rarely, however, are they found in pure culture but usually are 

 accompanied by other species of feeding caterpillars. 



Food plants. The pale tussock caterpillar rightly may be 

 termed a general feeder, it having been recorded by Beutenmuller 

 (17) as feeding upon thirty-one plants. According to the writer's 

 observations, sycamore is more commonly and severely attacked 

 than any other species. Not only are small trees of this species 

 attacked but large ones as well, the injury encompassing the upper 

 as well as the lower branches. 



Distribution. This insect is found, according to Packard (18), 

 as far west as the Mississippi River and extends from Canada to 

 Brazil and Paraguay. In Ohio it rarely is harmful as a shade tree 

 pest but occurs in greatest abundance in the hilly woodlands of the 

 southern part of the State. 



Natural enemies. Packard (18) reports that "some of the 

 larvae are infested by Tachinides and numerous species of Micro- 

 gaster." 



Control. Under present conditions, rarely is it advisable to 

 attempt the utilization of artificial controls. Spraying with arsen- 

 icals doubtless would prove efficient if the occasion demanded 

 their use. 



THE HICKORY TUSSOCK MOTH 



(Halisidota caryae Harris) 



While not so plentiful in Ohio as either of the foregoing species, 

 the hickory tussock moth has been reported as quite harmful hi 

 other sections of the country. 



Description. The adult is a beautiful moth having a wing 

 spread of about 2 inches. The fore wings are beautifully marked 

 by white spots on a light brown background and have the veins 

 lined with darker color. The hind wings are pure white. 



The larvae are exceedingly variable in appearance, presenting 

 different markings after each molt. The full-grown caterpillar, 

 however, is 1% inches long, and has been described by Doctor 

 Harris as follows: "White, covered with white hairs in short 

 spreading tufts, a row of eight black tufts along the back; two 

 long, black, pencil-like tufts on the fourth and tenth segments ; four 

 white on the second and third, two in the eleventh and twelfth. 



