173 



(PJiacorJiocn/^) and ant-Lear (Orycteropux), on \\lii('li tliey are 

 parasitic in the larval staj^c. If a stick be thrust souie little 

 distauce into one of these burrows and struck against the walls, a 

 larg'e number of these flies will usiuilly emerg-e. C. houeti and 

 C . cliocropliaga live in the deeper jjarts of the burrows in complete 

 darkness, and during' the day never emerge unless compelled. The 

 author says that after much patient watching" he has never seen 

 one fly come out voluntarily in the daytime, and when disturbed 

 they soon return. Observations showed that tliey regularly leave 

 the burrows at night. 



Details are given of various experiments which show that 

 Aucliineroiiiyia has but a feeble resistance to heat, Avhilst C'hoero- 

 myia can bear a temperature approaching 40° C, at least for a 

 short time. Tlie author also found tliat Choeromyia immediately 

 sought out pads of < otton soaked in water or heaps of moist earth 

 placed in the cage. The tendency of A lufeola to seek moisture 

 was not so marked. The adult flies feed upon sweet liquids and 

 various juices, and especially on excrement. The author had no 

 difficulty in cross-i)airing A. htteola and C. cltoerophajja in either 

 direction, but his observations led him to suppose that these crosses 

 are invariably sterile. The process of oviposition is as follows : — 

 TTie eggs are laid in the daytime in sliady places, the female runs 

 about on the surface of the soil in all directions dragging the 

 extremity of her abdomen on the ground and making a furrow with 

 it in the sand or dust. Her object being apparently to seek breaks, 

 holes or cracks in the soil filled with loose earth, and having found 

 one, she forces her abdomen deeply into it and deposits generally 

 only one egg, very rarely more. She then recommences the pro- 

 cess, and in this way spreads lier eggs over the soil in the hut. 

 Sometimes the eggs are laid round tlie natives asleep on the ground, 

 but the fly was never observed to lay directly on their bodies or in 

 the folds of tlieir clothing. CJioeromyia lays its eggs in the moist 

 soil at the bottom of the burrows of the PhacocJioerus and of the 

 Orycteropus either singly or in small groups. The number of eggs 

 laid is variable; tlie author noted the following in the case of 

 females of A. Ivteola, 83, 71, 58, 30, 34. Oviposition begins about 

 14-15 days after emergence, and a second oviposition may take 

 place as long as a month after the first one. The author experi- 

 mented on a number of eggs with a view to determining the efi^ect 

 of temperature and moisture, and came to the conclusion that those 

 of A. luteola are distinctly favoured by dry surroundings. When 

 exposed to a temperature of from 32-48° C. tM-o lots of eggs experi- 

 mented upon were killed. In the case of C. choerophaga, how- 

 ever, dryness retarded hatching. The hatcliing of the larvae from 

 tfie eggs is described, and the author says that 4 or 5 hours after 

 birth, if placed upon the naked skin, they immediately attempt 

 to bite. He points out that the position in which the eggs are laid 

 in the burrows and other places must frequently compel the larvae 

 to travel consideral)le distances before finding food. He therefore 

 experimented upon a number of larvae and found that those of 

 A. luteola were capable of living for 27 days after hatching Avith- 

 out any food whatever, and those of C. clioerophaya for 18 days. 



