16 



moderate cost. During January-March, 1914, some thousands of 

 parasitised pupae were forwarded to sheep-owners in different parts, 

 of New South Wales. Parasitised pupae of C. rufifacies collected in 

 November 1913, from the remains of a dead fly-blown animal, were 

 placed in a glass jar and in about twenty-four hours the small Chalcida 

 began to make their appearance in great numbers. They were then 

 transferred to ordinary glass lamp-chimneys, and to prevent their 

 becoming entangled in the cotton wool, the plugs were enclosed in a 

 piece of linen. A narrow strip of cloth was placed inside at one end 

 of the tube and kept moistened with a dilute solution of honey and 

 water, which appears to be a good substitute for the nectar of flowers, 

 upon which they probably feed under natural conditions. Several 

 pieces of meat were left exposed in the laboratory and were soon 

 infested with the eggs or maggots of several flies, including C. villosa, 

 C. oceaniae, Lucilia sericata, Sarcophaga aurifrons and other smaller 

 species ; the maggots were allowed to develop and pupate. The life- 

 history of the parasite being unknown, it was first attempted to para- 

 sitise the maggots, and although the parasites made several attempts 

 to insert their ovipositors into their bodies, they were prevented from 

 doing so by the constant wriggling of the maggots. Some fresh pupae 

 were then placed within the tube, on which the parasites immediately 

 began to lay their eggs. The method of ovipositing is described at 

 length, as well as the egg and pupa. The eggs hatch in about three 

 days, and the period of development of the larvae occupies about 

 seven and the pupal stage about five days. The males generally 

 appear a little before the females, and as soon as the latter emerge, 

 copulation begins. From each parasitised pupa, both sexes may 

 emerge, but females for the most part predominate ; it was noted, 

 however, that in one brood the males were in such extraordinary 

 preponderance that the progeny was necessarily much reduced. The 

 results under laboratory conditions have been most successful, the pre- 

 sent brood being the tenth generation from the original stock. Trouble 

 has, however, been caused by batches of the fly pupae dying from 

 time to time from some unloiown factor, the pupa rotting and drying 

 up within the puparium. It seems possible that this wholesale 

 mortality of pupae may be due to the unnatural rolling and 

 movement of them while being transferred from jar to jar. This 

 may injure the pupae in a critical stage of their process of histolysis. 



The number of eggs laid by a single female parasite at one puncture 

 has not been determined. From single puparia with which one 

 parasite had been placed in a tube and allowed to remain until death, 

 varying numbers developed, due perhaps to the size of the pupa, the 

 largest always containing the most parasites. In twelve puparia 

 thus isolated, the parasites developing in each varied from 37 to 10, 

 and as this number increases in a single Calliphora pupa, the adult 

 parasites are correspondingly smaller. One female placed in a tube 

 with fifteen puparia in three instances parasitised the whole, with the 

 exception of two which had decayed. The number of broods in a 

 year has yet to be determined, but between December and May, ten 

 broods developed under artificial conditions, which, however, may be 

 more favourable to the parasites, and the number of broods would 

 probably be less in nature. 



