12 BULLETIN 1028, U. S. DEPARTMENT OF AGRICULTURE. 



begin to oviposit immediately, for the bulk of issuance of tlie spring 

 generation parasite maggots is around June 12. The adults which 

 develop from these maggots will be found issuing from 7 to 11" days 

 later. Cocoons of the second generation, or those in which the para- 

 site is to pass the winter, begin to appear about the fourth of July, 

 but usually not in abundance until the second week in July. 



FEEDING OF PARASITIZED LARV/E VERSUS NONPARASITIZED LARV^. 



Several feeding records were kept of gipsy-moth larvae which were 

 known to be parasite-free as checks against similar feeding records 

 of larvse in which A. 7nelanoscelus had oviposited. The records show 

 that healthy gipsy-moth larvae eat from two to three times as much 

 as those which contain parasite maggots. These data were obtained 

 from feeding records made during the period between oviposition in 

 the caterpillar and issuance of the parasite maggot and the checks 

 were kept only for a similar number of days. The gipsy-moth larva 

 from which a maggot of ^4. melanoscelus has issued eats no more, al- 

 though it may live a few hours or as long as two weeks, the average 

 being seven days. 



LONGEVITY EXPERIMENTS. 



The tray shown in figure 1 (p. 4) was found most satisfactory for 

 the longevity experiments although glass tubes 8 by 2 inches were 

 used successfully for small numbers of parasites. 



The adults were fed on an equal mixture of honey and water, 

 sprayed on small pieces of sponge. It is important that the sponges 

 should be kept clean by thoroughly washing every other day. 

 Nothing but the food was inclosed in the trays with the adults, but 

 in the tubes they did better if a crumpled bit of paper was present 

 on which the parasites might rest and clean themselves. A. melanos- 

 celus in the tubes and trays, if kept in the light, lived for about one 

 week. When the containers were kept darkened by means of black 

 paper, the parasites remained rather inactive much of the time", and 

 lived considerably longer. 



In several experiments with adults issuing in spring and summer, 

 males and females lived for 30 to 32 days. In one case a female of 

 the summer issuing generation lived 35 days. There was very little 

 difference in the length of life of the adults, the females living" 

 slightly longer than the males. Without food they were able to live 

 only a few days. 



HOSTS OF A. MELANOSCELUS. 



Ratzeburg" gives as hosts in Europe Porthetna dis'par L. and 

 Stilfnotia salicis L. 



From field-collected material in this country A. melanoscelus has 

 been reared only from the gipsy moth. S. salicis^ the satin moth. 



i'^ Ratzeburg, Julius Theodok Christian, op cit. 1852. 



