406 MR. J. B. GATENBY ON THE BIONOMICS, EMBRYOLOGY, 



Other Proctotrypids are known to be parasites o£ insect larvae (15) ; and I am 

 inclined to support the view that the Proctotrypid is a parasite and not a 

 hyperparasite. I have been able to prove that Allotria, the Cynipid^ is a 

 hyperparasite. 



The Cynipid parasitic forms associated with Aphids apparently never 

 attack live Aphidse, but seek out the dried skins of those already parasitized 

 by an Aphidius. The same applies to many Chalcids. The latter insects^ as 

 far as my own experience goes, rarely attack active insects : I use the word 

 active in the sense that the host is able to retaliate. For instance, the 

 Pteromalids are Ohalcididse most often found pricking pupae, which of course 

 are unable to protect themselves. In the same way insect eggs, sluggish 

 coleopterous larvse, the pupse of other parasites [e. g. Microgasteridse), and 

 the parasitized carcases of Aphids are all objects of interest to Chalcids, and 

 in every case the victim is unable to resist. 



Ohalcididse are often spoken of as attacking live caterpillars, but all the 

 polyembryonic forms lay their ova in the eggs and not in the young larvse 

 of the host species. It is nevertheless true that some Chalcids do attack 

 most difficult objects, but the majority of species are either hyperparasites, 

 parasites on pupse^ or egg parasites. Imms (5) records carefully the para- 

 sitism of Aphelinus on a Coccid. However, a Coccid is not the sort of 

 creature which could retaliate against its tormentor in any way, and the 

 problem of oviposition before the Chalcid is much the same as when it is 

 laying its eggs in the ova of other insects or in pupse. The Braconid of the 

 Aphidivs type is an active, intelligent and busy insect; its habits are different 

 from those of some Chalcids I have noticed, which are sluggish, slow to take 

 wing, and which often examine their victim with meticulous and apparently 

 unnecessary care ; the Proctotrypidse and Cynipidse (the Allotrias) I have 

 not observed closely. Imms (5) and Marchal describe the oviposition 

 habits of certain Chalcids, and in every case the insect is extremely careful 

 and slow at work. I found the same in Trichogramma evanescens (9). Of 

 all the Parasitic Hymen optera the Ichneumonidse and Braconidse are the 

 cleverest and most artistic in their methods of attacking their proposed 

 victims. The manner in which a wasp or an ant proceeds to capture and 

 kill insects is rough as compared with the beautifully exact modus operandi 

 of the Aphidius [or of the Pompiliidse (fossorial wasps)]. 



The Parasitic Aphidius. (PL 26. figs. 17 & 18.) 



The parasite may be observed walking most unconcernedly over a colony 

 of Aphids, stopping here and there and then passing on ; when it finds an 

 Aphid which satisfies it, it attacks as shown in the above-mentioned figures. 

 While this is going on, the unfortunate Aphid does not try to walk away, but 

 it does move its legs, and often trys to kick, The Bracon takes not the 



