BtOLOGY OF LTMNERTUM VALIDUM. 81 



however, a few of the hirva? were able to Avithstand the action of the 

 amoebocytes and reach maturity. This immunity of the few is of 

 theoretical interest, as it would furnish a basis under proper condi- 

 tions for the evolutionary development of comj^lete host relationship. 

 It is not difficult to conceive that this parasite in the course of not 

 many generations might adapt itself so as to insure a minimum mor- 

 tality, and thus become an etfective enemy of the tent caterpillar. 



limnerium validum as a parasite of notolophus antiquus 



( Linnaeus). 



One of the most interesting of the experiments was started May 

 9, 1910, with the rusty vaporer moth {NotoJophus antiqiins Linnaeus) 

 as the host. One unfertilized female Limnerhim was confined with 

 25 small, third-stage caterpillars. The female remained alive for 12 

 days and oviposited freely in the caterpillars. 



Dissection work was commenced on June 17 and was continued at in- 

 tervals until June 30. In all, 10 caterpillars, 1 pupa, and 7 moths were 

 dissected. In the 10 caterpillars, a total of 40 eggs and eggshells was 

 found, and 8 larvse w^hich were all dead; in the 1 pupa, 1 eggshell 

 was found; and in the 7 moths, a total of 16 dead eggs and eggshells 

 was discovered, making a total of 57 eggs laid by the single female 

 in only 18 of the hosts. The results of the dissections are given mom 

 in detail in Table II. 



This experiment proved conclusively that this parasite is not at all 

 adapted to live at the expense of Notolophus. The larva^, even if they 

 were able to hatch, were killed by the host soon afterward, and at 

 least 6 of the eggs were unable to hatch. Two other eggs were found 

 with the dead larva only partially out of the shell. The larvae in 

 most cases were entirely destroyed by the host, so that all trace of 

 them was lost, except for the cast eggshell, yet a few resisted total 

 disintegration for a long period. The body tissues of the latter, 

 however, were broken down, so that nothing was left but the integu- 

 ment. The eggshells, or dead eggs with the embryo inside, resisted 

 destruction, on the other hand, to a remarkable degree, and were 

 found practically unharmed for a month or even longer after they 

 were laid, not only in the body cavity of the caterpillar and pupa 

 but even in that of the adult moth, and invariably well incased in 

 a sheath of amoebocytes. The eggshell in the single pupa dissected 

 was found adhering to the ovarian tubules of the host; in the case of 

 the moths, the eggs or shells were found many times just beneath the 

 integument of the abdomen, or among the ovarian tubules. One 

 female moth, which was in perfect condition and in no way incon- 

 venienced, carried of these eggshells. 



