158 



Experiments show that the punctures of the Chalcidid are primarily 

 for the purpose of nourishment, and that this nourishment at the 

 expense of the pupa is a specific food indispensable to oviposition. It 

 is only after at least one such meal that the fly is able to oviposit in 

 the successive pupae that it attacks, while of the pupae injured only 

 that one which has been used as a food supply is capable of 

 developing into an adult fly. AH pupae pierced after the first feed are 

 parasitised. 



The author has found N. brevicornis naturally parasitic upon 

 Calliphora erythrocephala and Phormia sordida, and has obtained 

 experimentally oviposition in GastropJnlus equi (intestinalis) and in 

 Glossina morsitans from Senegal. The parasite, in fact, attacks any 

 pupa that it can pierce with ease in order to obtain the juices 

 necessary for its nourishment. In the case of Gastrophilus and 

 Glossina morsitans the pupal cases were found to be too tough 

 for the adult parasite to emerge. One Chalcidid has been observed 

 to be capable of destroying four Muscids, especially when the pupae 

 are young ; when supplied with only old pupae, the parasites die from 

 lack of nutrition, being unable to pierce the pupal cases. The 

 destructive powers of N. brevicornis in connection with the pupae of 

 various flies and its perseverance in reaching and puncturing its 

 victims, even when the latter are concealed imder a light layer of earth, 

 indicate the possibility of its being used in the campaign against 

 Glossina, the pupae of which are hidden under bark, in holes in trees, 

 under light sand, etc. Various specific parasites of these flies have 

 been described during the last few years, but their biology is too little 

 understood to allow of their being utilised to any great extent. This 

 cannot be said of N. brevicornis, which can be obtained in large 

 quantities from the pupae of common Sarcophagid flies. The mode 

 of action of the parasite towards the pupae of G. morsitans has been 

 identical with that towards the Muscids of France. Young pupae 

 were searched for eagerly, the old ones avoided. The development of 

 the pupa of Glossina being slower (one month) than that of Calliphora, 

 the possible limit of infestation of Glossina is naturally more extended. 

 The impossibility of emergence limits the extent of parasitism, although 

 it does not reduce the immediate destructiveness of the parasite. 



The question naturally arises of the possibility of acclimatisation 

 of the insect. N. brevicornis seems experimentally capable of enduring 

 the usual temperature in which the tsetse-fly lives ; at 77° to 82° F., 

 which is the average temperature of Glossina haunts, its life is 

 apparently normal, the activity of the adults being increased and the 

 life-cycle appreciably shortened. A female reared at this temperature 

 produced 105 individuals in 12 days. A greater difficulty is the 

 maintenance of parasitism in the tsetse breeding grounds if the 

 continuity of parasitism at the expense of Glossina is not possible. 

 Tt is probable however that the Chalcidid will find some species of 

 flies other than Glossina in which successive generations can breed. 

 Experiments in this connection would be interesting. The method of 

 dissemination of the parasite among the Glossina haunts would be 

 simple. Having obtained a quantity of parasitised pupae of various 

 blow-flies, such as Calliphora, Lucilia, Sarcophaga, Chrysomyia, 

 Pycnosoma, etc., these would be distributed a few days before 

 emergence of the parasites, being either scattered by hand in the 



