BIOLOGY OF PARACOPIDOSOMOPSIS. 363 



material become sexual larvae, while those failing to receive such 

 descendants become asexual larvae. 



Various suggestions have been offered to account for the 

 presence of the so-called asexual larvae in Litomastix. Some 

 have suggested that they may not arise from the egg of Lito- 

 mastix at all, but are larvae belonging to an entirely different 

 species. Thus Wheeler ('10, p. 4O6) 1 expresses doubt as to 

 Silvestri's interpretation in the following language: "First, the 

 asexual larvae figured and described by this investigator are 

 suspiciously like certain very young ichneumonid larvae, and as 

 their development is not satisfactorily traced to the same cell- 

 masses from which the sexual Copidosoma larvae arise, it is not 

 improbable that the two larval forms really belong to two very 

 different parasites. In other words, Silvestri's Plusia caterpillars 

 were probably infested with ichneumonid in addition to Copido- 

 soma larvae. Second, I have been unable to find any larvae of 

 the asexual type in a number of American Plusia gamma cater- 

 pillars which were heavily infested with Copidosoma truncatellum. 

 Third, as in many species of Chalcididae larvae of Silvestri's 

 sexual type are able by their own endeavors to break down and 

 assimilate the tissues of their host, it seems improbable that a 

 single species should have developed a peculiar sexless and 

 moribund larva for this particular purpose." 



The subject clearly needs reinvestigation. In studying the 

 biology of Paracopidosomopsis I have found the same sort of 

 larvae as those described by Silvestri for Litomastix. An oppor- 

 tunity is thus afforded to restudy the question. In the present 

 paper only a brief history of the asexual larvae will be given. 

 As soon as sufficient material can be secured a detailed account 

 of the cytology and embryology of both types of larvae will be 

 published. 



The material used has been collected here at Austin during 

 the last three years. The species, Paracopidosomopsis floridanns 

 Ashmead, is very similar to Litomastix truncatellus. It lay its 

 egg in the egg of the common cabbage looper, Autographra bras- 

 sices. The parasitic egg develops in the body cavity or tissues 



1 Wheeler, W. M., 1910, "The Effects of Parasitic and Other Kinds of Castra- 

 tion in Insects," Jour, of Experimental Zoology, Vol. 8, pp. 377~438- 



