123 



These experiments prove that this parasite will attack and 

 breed upon three different kinds of wasps, of somewhat differ- 

 ent habits; but does not help to determine what it was iipon 

 which thej were originally discovered by Mr. Giffard, Un- 

 doubtedly it was either Odynerus or Pison. From its prolific- 

 ness, if it has but recently become introduced, it will soon be 

 numerous enough and sufficiently spread so that observers will 

 ere long be finding it, and mayhap under circumstances in 

 which its host can readily be determined. 



If it should prey chiefly upon Odynerus species, its presence 

 will be detrimental, as the Odyneri store up caterpillars for 

 food for their young; but if it should prey chiefly upon Pison 

 and Sceliphron its presence would be beneficial as these latter 

 wasps both store up spiders for their young. 



(ii) Ageniaspis sp. ( ?) 



This small Chalcid-fly I have found widely distributed in 

 the Hawaiian Islands; having found it breeding on Odynerus 

 larvae, or finding the remains of larvae upon which they have 

 fed, in nests of Odynerus nigripenms which I have examined 

 in Nuuanu and Makiki Valley, Oahu ; lao Valley, Maui, and in 

 Kau, Hawaii. In each of the places mentioned I have found 

 that the parasites were numerous. In one instance, I bred 105 

 parasites from one Odynerus nigripenms larva. Where I have 

 found parasitized larvae they have always been full-grown; 

 and when the parasites become fullgrown and pupate they have 

 eaten the entire contents of their host and completely fill its 

 skin. They can be seen thru the partially transparent skin, 

 packed so close that the skin bulges where it conforms to the 

 parasites inside. The adult parasites escape from the mud 

 cell of the wasp by gnawing a tiny hole thru the plug of 

 mud which sealed it. 



I first observed this parasite in December, 1905. In June, 

 1906, I made several attempts to breed them on the larvae of 

 Sceliphron caementarius ; but was entirely unsuccessful. The 

 other parts of its life cycle yet remain to be worked out. 



This is unquestionably a detrimental parasite, as it, so far 

 as I know, preys only on Odynerus species. 



