332 Annals Entomological Society of America [Vol. X, 



cages were quite large, being about three feet high and over three 

 feet in diameter, and each was placed over a young cherry tree 

 that had been cut back so as to be enclosed by the cage. They 

 were out-of-door cages without bottoms, so that any insects 

 emerging from the soil would be caught. On June 6th I 

 observed that two females had emerged in one of the cages 

 which I designated as cage A, and in another, one female saw-fly 

 had emerged. This second cage was designated as cage B, 

 These virgin females began to oviposit almost at once, and by 

 June 15, in cage A, I noted several eggs and six young larvae, 

 and in cage B another female had emerged, and a few eggs were 

 observed but no young slugs. By July 5, the female^ had died 

 in cage A, many growing slugs were present but no pupae. 

 These larvae continued to grow, and feed in a normal manner, 

 and then to pupate. 



On July 31 I noticed the first adult of the second generation 

 (Fi) had emerged. It was very active, and was moving about 

 the upper side of the cage. From now on adults from the 

 parthenogenetic eggs of the first generation females continued 

 to emerge rapidly. 



In all, 34 adult individuals were obtained from the partheno- 

 genetic eggs of the two females in cage A. All of them were 

 females, and all were healthy, active and vigorous. 



As fast as these females emerged they were isolated and each 

 placed in a gauze-bag breeding cage, which was placed around 

 the end of a cherry branch. These gauze bags were of sufficient 

 size to allow the females considerable freedom, and were placed 

 over the branches several weeks earlier after every leaf had been 

 carefully examined for foreign eggs. This was a precaution 

 against contamination, the bags excluding all the other saw- 

 flies in the orchard. 



Some of the data obtained for the rearing of these partheno- 

 genetic individuals are here presented in tabular form. 



