16 FIELD WORK AGAINST GIPSY AND BROWN-TAIL MOTHS. 



THE ADULTS. 



(PL I, figs. 1, 2.) 



The male moths ordinarily emerge from the pupae earlier than do 

 the females. The body of the male is light brown and the wings are 

 considerably darker and have prominent black markings. Male 

 moths are able to fly considerable distances and are especially active 

 during warm sunny weather. The zigzag motion of the flight of these 

 moths is characteristic of the species. The body of the female is light 

 buff. The abdomen, which is very large and almost completely filled 

 with eggs, is densely covered with short yellow hairs which are used 

 by the moth to protect the eggs as they are deposited in the cluster. 

 The wings are white, with prominent black markings, and, although 

 they are apparently of ample size, the female moth is not able to fly 

 on account of the weight of the body. The adult insects take no food, 

 and after mating, which takes place soon after emergence from the 

 pupa, the female begins depositing eggs. As a rule the egg cluster 

 will be found near the pupal case from which the female emerged, but 

 occasionally the moth will crawl a considerable distance, especially if 

 disturbed. When a search for egg clusters is being made the dis- 

 covery of a female pupal case is indication that an egg cluster is pres- 

 ent near by. Sometimes moths which emerge from pupae that are 

 attached to the branches of trees fall to the ground and deposit their 

 eggs on the trunks of surrounding trees or on leaves or rubbish. By 

 the time the egg cluster is completed, the abdomen has shrunken 

 greatly and in a few hours the moth dies. 



METHODS EMPLOYED IN WORK AGAINST THE GIPSY MOTH. 



SCOUTING. 



As the law enacted by the Massachusetts legislature in 1891 required 

 the state board of agriculture "to prevent the spread and secure the 

 extermination" of this insect, a determined effort was made to ascer- 

 tain the extent of the area infested. Men were trained so that they 

 were able to recognize the moth in all its stages, and as soon as they 

 had secured sufficient experience the most expert ones were sent into 

 the territory not known to be infested to make a thorough inspection. 

 As a result of this work, it was found that, while the area supposed to 

 be infested in 1890 covered 9 cities and towns in whole or in part and 

 embraced about 50 square miles, the pest had become established in 

 more or less numbers in 30 cities and towns, covering an area of 200 

 square miles. This spread had undoubtedly been going on for a num- 

 ber of years, and as the thickly settled sections became badly infested 

 the small caterpillars were easily conveyed long distances owing to their 

 habit of spinning down from trees onto vehicles or other moving 



