100 HAROLD H. Kl^^G BIONOMICS OF 



miles from its junction with the White Nile, several males were taken, 

 feeding on the flowers. Only two or three females were seen, but as there 

 were no cattle grazing in the immediate vicinity it is probable that they had 

 gone farther afield in search of more satisfying food. 



The eggs, obtained as described above, were deposited on May 2ord and 

 24th, on the undersides of the leaves of a water-weed. Unlike the eggs 

 of most members of the genus Tahanus, they were not closely packed in a 

 rounded mass, but placed vertically and separately, though in a cluster. 

 They hatched on May 30th, and the tiny larvae were divided into three 

 lots, and placed in glass basins containing mud^ water and growing grass. 

 These basins for purposes of reference were labelled A, B and C. 



At the time wdien the eggs hatched, the writer was in the Sud region, 

 where it was impossible to land and obtain any subterraneous insect larvae 

 or tiny fresh-water crustaceans for them, so they w^ere offered the expressed 

 stomach-contents of gorged female ticks — Bldpiceplialus simus — taken from 

 a dog. A few fed once or twice but the majority refused, and all buried 

 themselves in the mud. 



On June 11th, the larva3 from A were transferred from mud to clean 

 river-sand and \Nater, and given freshly killed mosquito larvse. They fed on 

 these readily and grew apace, though at greatly varying rates. 



The larvae in B were also given mosquito larvae from June 11th, but they 

 refused to feed, and the mud in which they were living Avas several times 

 allowed to dry up. On July 11th they were placed in clean river-sand and 

 water, and at once began to feed and grow. 



On July 19th the writer returned to Khartoum and, owing to the difficulty 

 in obtaining mosquito larvae, changed their diet to freshly killed and bruised 

 earthworms. They did not take readily to this food, and some died, while 

 others disappeared from their basins. At the time it was thought that they 

 had become cannibals, but eventually it was found that they were being- 

 taken by mice. The stock of larvae from A and B had by this time become 

 reduced to one^ wdiich appeared to be full grown, and so was killed and 

 preserved. 



On July 26th the larvae from C w^ere transferred to clean river-sand and 

 water. It was then fifty-seven days since they had emerged from eggs, and 

 they had spent a great part of that time in a dry cake of mud. Occasionally 

 this mud had been moistened, and food offered them, but they had very 

 rarely taken it. Most of them were alive, but with the exception of a few 

 w^hich were slightly larger than when just hatched, they had not grown at 

 all. They now, under more favourable conditions, fed readily on a mixed 

 diet of earthworms and mosquito larvae and grew, some rapidly, others more 

 slowly. On September 3rd-4th one pupated, lying on the surface of the 

 sand, partly submerged in water, and six days later gave rise to an adult 

 female. 



