380 Report of the Department of Entomology of the 



GIPSY AND BROWN-TAIL MOTHS. 



These insects have been for many years destructive pests' in New 

 England. They are very injurious in orchards, but they have 

 largely derived their reputation as noxious insects from their 

 ravages on shade and woodland trees. One small infestation of the 

 gipsy moth has already been located in this State; and because of 

 the commercial intercourse and the close proximity of New York to 

 the infested areas of New England the time is doubtless not far 

 distant when one or both of these insects will establish themselves in 

 our fruit-growing sections. Orchardists should familiarize them- 

 selves with the appearances and habits of these insects. 



GIPSY MOTH. 



Porthetria dispar Linn. 



The gipsy moth is a native of Europe. It occurs there in destruc- 

 tive numbers at intervals of several years, when it defoliates large 

 areas of forest. It was first introduced into Mas- 

 sachusetts in 1868 and by 1890 it had spread and 

 become a serious pest in the eastern part of the 

 state. In subsequent years it has established itself 

 in many parts of New England and the authorities 

 have undertaken extensive means of repression. 

 The spread of the gipsy moth from one tree to 

 another of its own accord is largely dependent 

 upon the caterpillar stage (Plate XXVIII, fig. 4), 

 for the female (Plate XXVIII, fig. 5) does not fly 

 readily. However, all stages of the insect may be 

 transported by other agencies, such as wagons, auto- 

 mobiles and shipments of freight. By this means 

 the pest has been distributed over the eastern 

 part of Massachusetts and into adjoining states. 

 The caterpillars feed on the foliage of practically 

 all plants, and if uncontrolled will kill most shade 

 trees in two or three years. Coniferous trees are 

 said to be killed after one defoliation. 



Life history. — The eggs are laid during July and 

 August in large, oval masses, covered by yellowish 

 hairs from the body of the female. They may be 

 deposited on the bark or in cavities of the trunk, 

 on the underside of leaves, on fences, walls or houses, and on boards, 

 boxes or any kind of object that adjoins infested trees. The eggs 

 hatch about the first of May and the caterpillars are full grown by 

 midsummer. They are then about three inches long, of a dusky 

 color with a double row of eleven spots down the back; the first 

 five pairs are blue and the remaining six red. (Fig. 55.) In July 

 or early August they change to the pupa stage, which is often enclosed 



Fig. 55. — Diagram 

 of Markings on 

 Gipsy Moth 



Larva. 



