LIFE -HISTORY OF LIOTHULA OMNIVORA. 159 



eggs, except those which reach a dipterous maggot never hatch- 

 ing, or it must by some extraordinary means be able to single 

 out those caterpillars infested by Diptera and oviposit in them, 

 occasionally perhaps missing the maggots lying within, as Mr. 

 Bignell conjectures in the case of Abraxas grossulariata (Entom. 

 xiii. 245). Both of these suppositions are, in my mind, contra- 

 dicted by the fact that out of six dipterous pupae taken from a 

 single caterpillar only one was infested with Chalcids, and that 

 contained eighteen. Now it would be a remarkable circumstance 

 indeed for a female Chalcid to oviposit in a caterpillar eighteen 

 times, striking an enclosed maggot every time, and not any of 

 the five others once. I prefer to consider, until actual observation 

 proves it fallacious, that both Eurigaster and the Chalcid enter 

 the Liothula's case together by the posterior aperture, the latter 

 possibly clinging to the former. The Dipteron then lays a 

 number of eggs on the skin of the caterpillar, as is the case 

 ■with all parasites of the order, and the hyperparasite oviposits 

 in one, or perhaps occasionally more, of these ; the dipterous 

 maggots then eat their way into the caterpillar, both insects 

 afterwards developing, as we have seen above.* 



This theory may of course be upset at any time by the 

 discovery of the actual method ; but, with the facts at present at 

 my disposal, I think the above is the most feasible explanation, 

 and, moreover, that it is not without a parallel in the insect world 

 anyone will admit, who is acquainted with the life-history of the 

 genus Sitaris among the Coleoptera. 



Karori, Wellington, New Zealand, March 25, 1885. 



* Sir Sidney Saunders met with a similar difficulty in the case of a Chalcis 

 hyperparasitic on a Sarcophaga living within the body of a locust {(Edipoda cruciata, 

 Charp.). He says, " Hence the question arises, how the parent Chalcis obtained 

 access to the Sarcophaga larvae for the purpose of depositing her eggs? It might be 

 supposed that this opportunity was afforded at the time when the adult larva quits 

 the body of the locust to undergo its final metamorphoses in tlie earth. Eut such 

 could not have been the case in this instance, when the transition took place within 

 a closed box remote from their accustomed haunts. The egg must therefore have 

 been deposited at an antecedent period, either while the larva was within the body 

 of the locust, or probably still earlier, when the newly-batched larva was about to 

 penetrate into the body of the locust." (Proc. Ent. Soc. Loud., 1881, p. xxv.) 



