188 OHIO EXPERIMENT STATION: BULLETIN 194 



"When full grown the caterpillars are 1/4 inches long. Tliey 

 are dark brown with a sprinkling of orange. Long', fine, red- 

 dish hairs cover the, body, and a row of conspicuous white hairs 

 runs along each side. Like the caterpillars of the tussock and 

 gypsy moths, they bear bright red eversible tubercles on the top of 

 the sixth and seventh abdominal segments."* 



Besides doing great injury to the trees in badly infested 'dis- 

 tricts, the caterpillars are equally obnoxious because of the poison- 

 ing effect the spines trom the hairs of their bodies have upon human 

 flesh. Contact with the insect's body, with cast skins as they are 

 blown about, with the cocoons or with clothing in which the spines 

 have gained access, may cause the characteristic irritating eruptions. 



The cocoons are placed upon the leaves or in some sheltered 

 position. They are lightly covered with the brown hairs from the 

 tip of the female abdomen. 



As to food plants, according to Dr. Felt, the insect feeds upon 

 such fruit trees as the pear, apple, plum, and cherry, and upon the 

 following forest trees: oak, maple and elm. 



The remedial measures are comparatively simple, con- 

 sisting of the collecting and destroying of the conspicuous winter 

 nests. Spraying with arsenicals is also to be relied upon, but the 

 former is preferable because of the smaller expense involved 



The GyfsyMoih, '^^'^' ^^^^^^^ *^^ preceding insect, is' 



Porihetria disfar l^inn. one that Ohioans may happily say does 



not occur within the borders of the state. 

 It was introduced into Medford, Mass., in 1868 or 1869, but did not 

 develop in excessive numbers until 1889, when the attacks became 

 very severe in the locality of its introduction. 



At that time the state of Massachusetts began making annual 

 appropriations for the purpose of combatting the pest and during 

 the nine years following over $1,000,000 was expended. During that 

 time the insect spread slowly, and since 1899, when the appropria- 

 tions were discontinued, more rapidly, so that at the present time a 

 considerable area of Massachusetts is infested, and the infestation 

 has spread to at least one of the neighboring states (Rhode Island.) 

 "The eggs of this insect are deposited usually in round or oval 

 patches on a piece of bark and then covered with the buff-colored 

 scales from the underside of the female's abdomen. A completed 

 egg-mass looks very much like a. small piece of sponge. The egg- 

 mass may be found on stones, in tin cans, and in fact on almost any 

 fixed object near at hand, preferably on the under surface, particu- 



*Bul. 108, Maine Agrricultural' Experiment Station, i 



