A. K. Camkron 55 



7. Co]))ih(lio)i, Oviposifinn (uxJ E(j(j Period. 



The Aiithomyiidao aic very restless active flies, and in captivity 

 they seem to be entlowed with such exuberance tliat they rarely become 

 accustomed to the narrow confines of a wire-gauze breeding cage, such 

 as was used throughout in the experimental learing of P. hyoscyanii. 

 In many ways these roomy cages, as manufactured by Voss, commend 

 themselves for observational purposes, built as they are of stout sheet 

 iron, with sides of wMre gauze, back wall and sloping roof of iron and 

 with a glass panel front. On one side there is a hinged door and basally 

 a detachable, well-fitting tray of zinc for containing soil, into which the 

 fully mature larva of the species in question burrows previous to pupating. 

 A potted plant of belladonna (the host plant of /-*. hijoscijami) was intro- 

 duced into the cage and periodically watered to maintain its freshness 

 and ensure its growth. The stout heavy basal part of the cage may be 

 detached from the upper, lighter portion by the removal of two small, 

 bent, iron rods, one on each side, fitting closely into hollow projecting 

 iron cylinders placed alternately on the upper edge of the basal and 

 the lower edge of the upper part. When in position these rods fix the 

 two parts of the cage firmly together. 



Copulation takes place after the lapse of a number of days from the 

 time of exit of the female from the pupa case. This interval is deter- 

 mined by one or more factors, such as the constitution of the female, 

 the kind of nutrition and the amount of food, the time of year, and 

 the prevailing weather conditions. For instance in the breeding cages 

 kept in the insectary which had free access to daylight and where the 

 conditions were, as nearly as possible, similar to those in the open, 

 the flies were never observed to copulate when the sky was overclouded. 

 Indeed, in the summer and autumn of 1912, owing to some reason or 

 other, copulation never occurred in the cages and consequently no eggs 

 were laid. Never yet has it been my good fortune to observe the act 

 of pairing outside, but on Aug. 26th, 1913, the behaviour of the flies 

 in this respect w^as noted for the first time and the accompanying sketch 

 (Text-fig. 1) drawn from life. 



As represented in the figure, the male stands above the female wnth 

 its fore tarsi applied to the thorax and resting on the shoulders of the 

 wings which are kept divaricate. The middle tarsi of the male embrace 

 laterally the fifth abdominal segment of the female, whilst the hind tarsi 

 encircle the extremity of the latter's abdomen. The femora and tibiae 



