30 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 



duction to any one of the different countries to which it has been 

 carried. Its success has been more perfect than that of any other 

 beneficial insect that has so far been tried in this international work. 

 There are good reasons for this — reasons that do not hold in the 

 relations of many other beneficial insects to their hosts. In the first 

 place, the Icerya is fixed to the plant; it does not fly, and crawls very 

 slowly when first hatched, and later not at all. The Novius, however, 

 is active, crawls rapidly about in the larval state, and flies readily 

 in the adult. In the second place, the Novius is a rapid breeder, and 

 has at least two generations during the time in which a single genera- 

 tion of the host is being developed. In the third place, the Novius 

 feeds upon the eggs of the Icerya. And in the fourth place, it seems 

 to have no enemies of its own. This is a very strange fact, since other 

 ladybirds are destroyed by several species of parasites. For example, 

 as will be shown later, native American ladybird parasites brought 

 about a great mortality in the larvae of the Chinese ladybird imported 

 from China into America at a later date by Marlatt. The hymenop- 

 terous parasites of the widespread genus Homalotylus feed exclu- 

 sively, in ladybird larvae, which are frequently also fairly packed with 

 the minute hymenopterous parasites of the genus Syntomosphyrum, 

 while the adults are often destroyed by Perilitus, Microctonus, and 

 Euphorus. 



The astonishing results of the practical handling of Novius drew 

 attention more forcibly than ever before to the possibilities of this 

 kind of warfare against injurious insects, and although its perfect 

 success as an individual species has never been duplicated, very 

 many efforts in this direction have been made, some of which have 

 met with measurable success and some with very positive results of 

 value. 



Introduction of Entedon epigonus Walk, into the Unted States. 



In 1891, with the assistance of Mr. Fred Enock, of London, Riley 

 introduced puparia of the Hessian fly (Mayetiola destructor gay) 

 infested with the chalcidid parasite Entedon epigonus Walk, into 

 America. These were distributed among several entomologists dur- 

 ing the spring of 1891. One American generation was carefully 

 followed by Forbes in Illinois, and four years later (in May, 1895) 

 the species was recovered by Ashmead at Cecilton, Md., where a 

 colony had been placed in 1891. Thus the introduction was appar- 

 ently successful, but if the species still exists in the United States 

 it must be rare, since extensive rearings of Hessian-fly parasites have 

 been made by agents of the Bureau of Entomology in many different 

 parts of the country during the past few years and not a single speci- 

 men of the Entedon has been recognized. The Maryland locality, 

 however J it should be stated, has not been visited by an entomologist 

 since Ashmead's trip in May, 1895. 





