( xxx vii ) 



also be laid elsewhere, inasmuch as the larvae appeared in 

 the bowl of water in the glass case (containing the captive 

 ants) into which he had introduced a number of gnats. The 

 larvae are easily recognised by their yellowish-white colour and 

 by their habit of lying on the bottom of the vessel. Jacob- 

 son records that those nests of Cremastogaster which were 

 most freely attended by the Harpagomyia consisted almost 

 entirely of the small type of workers, and lie considered that 

 this was brought about by the amount of food taken from 

 the ants, and therefore diverted from their larvae. He 

 furthermore states that he had never found females, but- 

 only males and workers, in such nests. Mr. Donisthorpe said 

 that this observation was of special interest to himself, as 

 he had been working for some years on the causes by which 

 females are produced in ants' nests. He had, for three years 

 running, bred winged females from eggs laid in captivity 

 by a community he had kept in an observation nest for over 

 seven years, and for the first time last year in another com- 

 munity he had observed during five years, and he was of 

 opinion that these positive results had been brought about 

 by the amount of food with which these two nests had been 

 supplied. Ants have been kept in captivity by very many 

 myrmecologists for over 100 years, and in all that time winged 

 females have only once before been produced from eggs laid 

 in captivity, viz. when Lord Avebury bred five winged fusca 

 females in an observation nest in 1880. The last-named 

 observer also thought that his success might be accounted 

 for by the fact that this community had been very well fed. 



Some authorities also considered that the presence of 

 pseudogynes in ants' nests was brought about by the ants 

 taking too much interest in the beetle Lomechusa and its 

 larvae, and in consequence neglecting their own brood. It 

 will be of much importance if Mr. Farquharson should find 

 that those nests of Cremastogaster which are most attended 

 by the Harpagomyia in 8. Nigeria are also unable to produce 

 females. 



Mr. Donisthorpe had also found flies of the genus Mihchia 

 associated with ants in this country, viz. M. ludens, Wahl., 

 with A. (D.) fuliginosus at Darenth Wood in 1909, and again 



