Miss Haviland, Note on the Life History of Lygocerus 293 



Preliminary Note on the Life History of Lygocerus {Procto- 

 trypidae), hyperparasite of Aphidius. By Maud D. Haviland, 

 Fellow of Newnham College. (Communicated by Mr H. H. 

 Brindley.) 



[Read 10 November 1919.] 



Plant lice are frequently parasitized by certain Braconidae of 

 the family Aphidiidae. The parasite oviposits in the haemocoele 

 of the aphis, and the larva, during development, consumes the 

 viscera of the host. At metamorphosis nothing remains but the 

 dry skin, within which the Aphidius spins a cocoon for pupation. 



At this stage, the Aphidius itself is liable to be parasitized in 

 turn by certain Cynipidae, Chalcidae, and Proctotrypidae. The 

 two former are known to be hyperparasites, but the Proctotry- 

 pidae have hitherto been considered doubtful, although some 

 writers have suspected that they are hyperparasites of the Aphidius, 

 and not parasites of the aphis. Gatenby in his paper: " Notes on the 

 Bionomics, Embryology, and Anatomy of certain Hymenoptera 

 Parasitica" (Journ. Linn. Soc. 1919, vol. xxx, pp. 387-416) says: 

 ". . .1 am inclined to support the view that the Proctotrypid is a 

 parasite, and not a hyperparasite." 



The following is a summary of some observations made in the 

 summer of 1919, on two Proctotrypids of the genus Lygocerus. 

 I am much indebted to Professor Kieffer, who has kindly identified 

 them for me as L. testaceimanus, Kieff., hyperparasite of Aphidius 

 salicis, Hal., parasite of Aphis saliceti, Kalt., from the willow; and 

 L. cameroni, Kieff., hyperparasite of Aphidius ervi, Hal., parasite 

 of Macrosiphum. urticae from the nettle. The following notes 

 probably apply to both species, but the observations were made 

 more especially upon the latter. It was found also that in cap- 

 tivity L. testaceimanus would oviposit on Aphidius ervi. The 

 Proctotrypids do not confine their attacks to the Aphidiidae, but 

 their larvae may also be found feeding on the larvae of other 

 Chalcid or Cynipid hyperparasites of that family ; and indeed once 

 or twice were observed upon dead pupae of their own species. One 

 remarkable instance of hyperparasitism came under notice. An 

 aphis {Macrosiphum urticae) was parasitized by an Aphidius (A. 

 ervi). The latter had been hyperparasitized by a Chalcid, of species 

 unknown, which immediately after pupation had been attacked 

 by another hyperparasite, either Chalcid or Cynipid, whose identity 

 is not yet determined. This second hyperparasite in turn had been 

 attacked by Lygocerus cameroni, and the larva was in the second 

 instar when the cocoon was opened. We may ask, where are the 

 limits to this hyperparasitism? 



