34 W. A. LAMBORN. 



Syntomosphyrum glossinae, Wtrst. 



Evidence confirming completely my previous opinion that these insects are hyper- 

 parasitic on MiUilla glossinae has now been obtained. On 20th June a large number, 

 comprising both sexes, were bred out from a tsetse pupa found in the vicinity 

 of Monkey Bay, pairing taking place forthwith. A number of pupae suspected of 

 being parasitised by the Mutilla, one with the cocoon of the latter showing through 

 a fracture of the puparium, were put into two boxes, each containing two female 

 Chalcids and one male, and the act of oviposition was shortly afterwards witnessed, 

 the female re-opening, by means of the hard pointed extremity of its abdomen, the 

 perforation made and sealed by the female MutiUa. The operation took some hours, 

 and it was possible day by day to note the position of the pupae on which the Chalcid 

 was sitting and afterwards to set them aside, so that in a number of instances precise 

 data are available. In no case did emergence of the offspring take place through the 

 perforation utilised for oviposition, but a fresh opening was bored, usually at either 

 end, and in four cases the offspring emerged through two separate openings. The 

 female Chalcids were readily dealt with in captivity, surviving till the first week of 

 July, a period of about two weeks. 



The evidence shows that the MutiUa may be attacked by the Chalcid at any stage 

 in its development, whether as larva or pupa. This has been confirmed further by 

 an examination of the pupa-cases from which the Chalcids had emerged. A majority 

 of these showed within no vestige of the Mutilla, indicating that it had probably been 

 attacked in the larval stage, while about 20 per cent, exhibited the cocoon with the 

 tiny perforation at one end. 



The fecundity of these Chalcids would seem, as in other cases, to be a measure of 

 the keenness of the struggle for existence, for though no less than 2,340 wild pupae 

 have now been obtained, in one instance only have they yielded the insects. The 

 proportion of empty pupa-cases that seem to have contained them is higher, for out 

 of 9,285 found between 7th April and 2nd June 351, or about 3 per cent., showed 

 the pinpoint opening, while it was seen in 63 of the 7,731 pupa-cases (less than 1 per 

 (Cent.) found from 22nd August to 16th October. 



Further confirmation of the rarity of Mutilla glossinae in the proclaimed area is 

 ;afforded by the absence of pupa-cases showing evidence of this attack. 



I am carrying on the strain of Syntomosphyrum with a view to ascertaining their 

 action in regard to pupae parasitised by the new Mutilla. 



Eupelminus tarsatus, Wtrst. 



From a total of 1,210 living pupae collected at Monkey Bay up to 2nd June a single 

 one yielded one of these insects. But since then three more pupae out of an additional 

 762 collected in the same neighbourhood have yielded them, two pupae containing 

 two females each, and the third two males and five females. The advent of the 

 males and the facility with which the insects can be kept alive in captivity have 

 made it possible to ascertain the part they play in the life-history of morsitans. 



As with the other parasites considered, coitus took place very shortly after 

 emer^rence and prior even to feeding, and the females commenced to oviposit in 

 morsitans pupae within a couple of hours. They were supplied with a large number 



