THE GIPSY AND BROWN TAIL MOTHS 



I t 



during a decade, amounted to $1,155,000. The work was so suc- 

 sessful that in many sections badly infested in 1890, gipsy moth 

 caterpillars were remarkable for their scarcity in 1898 and following 

 years. Residents of the infested sections almost forgot that there 

 had ever been such a pest, and made light of the close exterminative 

 methods then in vogue. Unfortunately the work was abandoned 

 at this stage and the insect has had an opportunity of multiplying 

 almost without restriction during the past five years, greatly 

 extending its range and causing serious depredations as described 

 in a previous paragraph. 



Life history. The winter is passed in an egg mass remarkably 

 resistant to atmospheric and other changes. Experiments have 

 shown that even when egg clusters were broken up and freely 

 exposed to the elements, their contents were apparently unharmed 

 and a normal proportion of caterpillars appeared at the usual time, 

 which, in the vicinity of Boston, is from the last of April to the 

 middle of June. The feeding period extends from the first of May 

 to about the middle of July, the caterpillar requiring from about 

 9 to 11 weeks to complete its growth and enter the pupal stage. 

 The recently hatched caterpillars remain on the egg clusters from 

 one to five or more days and then commence feeding on the leaf 

 hairs. Soon they eat out small holes in the foliage and after the 

 third or fourth molt about as many feed on the edge of the leaf as 

 eat out holes. The caterpillars are largely nocturnal, remaining 

 in clusters on. limb or trunk or hiding in some crevice during the 

 day, beginning between 7 and 8 o'clock in the evening leisurely 

 to ascend the tree, where they feed on the foliage at intervals during 

 the night, descending about 3 o'clock in the morning. The gipsy 

 moth caterpillars assemble in just such masses as those formed 

 by our native forest tent caterpillar, Malacosoma dis- 

 stria Hiibn., so abundant in sections of New York State about 

 1900. This imported species is just as destructive as our native 

 form and much more dangerous because of its feeding upon a large 

 variety of plants. 



The caterpillars transform to pupae during the month of June, 

 moths appearing from the latter part of June to the latter part of 

 July, and belated individuals may even be found in September. 

 Males emerge in advance of the opposite sex and shortly after 

 females appear, pairing takes place and eggs are laid. The em- 

 bryos or very young caterpillers are frequently well developed 

 within the eggs in two or three weeks after oviposition and as a rule 

 they do not emerge till the next spring. One case is on record of 



