ZENILLIA AXD ALLIED GENERA SELLERS 53 



reared from Malacosoma americana: One female paratype, 10000G; 

 3 female paratypes, lOOOOi; 1 female paratype, 10070 C5; 1 male 

 paratype, 10070 J23; 1 male paratype, 11701 J3a) ; and 14 field- 

 collected specimens including 1 male and 2 female paratypes from 

 Melrose Highlands, Mass. (Webber) and 1 male paratype from Blue 

 Hills, Mass. (Webber) . 



Now that the identity is clear, the biology can be further discussed. 

 It has been observed that this species emerges from hibernation 

 about a week later in the spring than Carcelia laxifrons does. This 

 would seem to be quite normal and natural, as the preferred hosts 

 of Carcelia malacosomue, namely, Malacosoma disstria and M. ameri- 

 cana, would have to develop from the egg to a suitable size for parasiti- 

 zation; whereas the preferred host of C. laxifrons, namely, Nygmia 

 phaeorrhoea, which hibernates as a larva, would develop to a suitable 

 size earlier. The males precede the females in emergence by a day or 

 two and prefer to mate with the freshly emerged females. The 

 average length of time spent in copulation is from 15 to 20 minutes. 

 The elapsed time from copulation to commencement of oviposition 

 is from 7 to 8 days. The egg hatches in from 45 minutes to 5 days 

 after deposition, depending upon how far the larva has incubated 

 at the time of oviposition. (The observation supports both Pantel's 

 and Townsend's observation on Carcelia cheloniae and C. laxifrons.) A 

 record of oviposition of 510 eggs was secured from an unfertilized 

 female. The eggs are deposited anywhere on the dorsal hairs of the 

 host and rarely on the skin. The larva hatches from the opposite 

 end of the egg from which the pedicel is attached. After emerging 

 from the egg, the larva continues its way down the side of the egg, 

 along the hair upon which the egg was laid, until it reaches the body 

 of the host. The larva then migrates to a suitable point of entrance 

 into the host. The full-grown larva emerges from the host about 

 3 to 4 weeks after oviposition and pupates. 



The following experiment was performed in the spring of 1926: 

 Fertilized females of Carcelia obtained from Malacosoma americana 

 deposited 60 eggs on 17 tent caterpillars (M. americana), 2 cater- 

 pillars lived to produce 3 puparia; 114 eggs were deposited on 36 

 browntail moth caterpillars (Nygmia phaeorrhoea) and no puparia 

 were recovered although the caterpillars lived eventually to produce 

 adult moths. The females oviposited with equal eagerness on either 

 form, and all the eggs hatched. Subsequent taxonomic investigation 

 substantiated this experiment. There has never been a Carcelia 

 characterized in part by the yellowish femora (nialacosomae) reared 

 from any field-collected larvae of the brown-tail moth at the Gypsy 

 Moth Laboratory. 



