APANTELES MELANOSCELUS GIPSY-MOTH PARASITE. 5 



inches, for confining several. As the Apanteles are usually active 

 and soon exhaust themselves if allowed to remain in the light, the 

 tubes or cages containing them were kept dark when not in use. 



Records of oviposition were obtained in the following manner: A 

 glass tube containing a single female was brought into the light and 

 a parasite-free gipsy-moth larva was introduced on the point of a 

 small camel's-hair brush. As soon as the parasite oviposited in the 

 caterpillar, the larva was removed to a can for rearing. This pro- 

 cedure was continued as long as a female would oviposit readil3^ 

 As soon as she began to show a lack of interest in the gipsA-moth 

 larv8e, she was returned to the dark to rest and a fresh female given 

 an opportunity to oviposit. 



After the first female had rested for an hour or two she was again 

 brought into the light and presented with gipsy-moth larvae as 

 before. This process was continued with several females throughout 

 their life. 



The parasitized larvae were kept isolated in cylindrical cans, 

 which measured 2| by 2 inches, there fed, and kept for future study. 

 The structure and length of the various larval instars were determined 

 by daily dissections of these parasitized caterpillars. 



LIFE HISTORY. 



Apanteles melanoscelus hibernates as a third-stage maggot within 

 its tough sulphur-yellow cocoon. Under field conditions the adults 

 emerge from their cocoons over a period of about three weeks. Emer- 

 gence is at its height when the gipsy-moth Q.gg hatching is at its 

 maximum, usually during the second week in May. The period of 

 emergence of adults from cocoons kept at the laboratory where all 

 of the cocoons are held under the same conditions is five or six daj^s. 

 The majority of the males emerge during the first four days; the 

 females, beginning to emerge on the second day, continue emerging 

 for four or five days, the bulk of emergence being on the third day 

 after the first appearance of either sex. The adult escapes through 

 a circular hole which it cuts at the anterior end of the cocoon. 



Females of A. melanoscelus are ready for mating or for oviposi- 

 tion within two or three hours after issuing. They oviposit just as 

 freely whether they have been fertilized or not, and, as is the case 

 with many parasitic Hymenoptera, they often reproduce partheno- 

 genetically. 



This species does not copulate readily when enclosed in glass vials 

 or small cages, but was often observed in coition in the large breeding- 

 chamber (PI. V, C). The male approaches the female in the usual 

 state of excitement with its antennae and wings constantly vibrating. 

 The act of copulation is a matter of a few seconds. 



