124 A TOUR AMONG THE ISLANDS 



formed of boulders, except for a shingle beach at the 

 northern end. 



In the preliminary circumnavigation five Enswa-swa were 

 seen, but no crocodiles. Rumfua is decidedly a " spider 

 island," and the masses of their webs among the dense 

 bush prevented one from walking over it. A great many 

 hippo lairs were seen, so that the island seems to be a 

 favourite sleeping place for them. Birds were scarce ; 

 there were no weavers or sunbirds, and only one " Kung- 

 uvu " flycatcher was seen. A large flock of egrets was 

 noted on the shore. Egg capsules of Maniidae were 

 particularly noticeable, though the insects themselves 

 were not abundant at the time. 



The only butterflies noted were three Lycaenids and a 

 Nymphaline, viz. the common T. telicanus and an equally 

 common Lycaenesthes, and the rare Aphnaeus orcas ; the 

 solitary Nymphaline was a fine Euralia. 



On March 22nd, with Fiske's departure, our joint tour 

 came to an end. Apart from the results obtained bearing 

 on the bionomics of Glossina, many extremely interesting 

 facts had been noted regarding the predominance on 

 certain islands of one or another type of insect ; and it 

 was very interesting to see how, when the great spiders 

 abounded, insectivorous birds were absent and the " balance 

 of nature " was maintained by an abundance of Mantidae 

 or Asilidae keeping down insects which might otherwise 

 have been devoured by birds. 



