69 



but the attack is not usually made by the insect at the point upon 

 which it at first settles. In one case I witnessed Tdbanus testa- 

 ceiventris, Macq.* alight upon the back of a native at the wheel of 

 a steam launch in which I was travelling, and, although it crawled 

 over the man's bare flesh for some time, it did not attempt to bite 

 until it had reached the outside of a vest which he wore, when it 

 tried to drive its proboscis through the material in order to do so. 

 The bites of all the species I met with, and which I had personal 

 experience of, resulted in a painful swelling, which generally 

 subsided in a few hours. The species which gave most trouble 

 upon the creeks of S. Nigeria were T. gabonensis,^ T. ihoracinus 

 and T. nigrohirtus,l while in N. Nigeria T. tceniola, T. fasciatus 

 and T. testaceiventris* were most conspicuous. T. biguttatus, of 

 which the male is differently marked to the female, I found upon 

 three or four occasions in a verandah in Lokoja, but it never seemed 

 inclined to bite, only crawling slowly about flowers or verandah 

 posts. On two occasions I took specimens of T. obscurissimus 

 upon the ground, having lost both wings. I can offer no explanation 

 for this, although the coincidence seems rather remarkable." 



The species of Tdbanus deposit their white, 

 Life-history, brown, or black eggs in rounded masses on the 



leaves and stems of plants overhanging water 

 or growing in wet ground, sometimes also on the exposed surfaces 

 of partially submerged stones. The eggs, which are elongate 

 spindle-shaped, are usually between 2 and 3 mm. in length, and 

 always deposited in several layers ; a single egg-mass may contain 

 upwards of 400 or 500 eggs, but the number is often much 

 smaller. 



The larvce, which are of the usual Tabanid type and carnivorous, 

 live in water, mud, damp earth, or sand, feeding upon other aquatic 

 larvae, snails, earthworms, and small Crustacea. Development is 

 slow, and the larval stage lasts for several months ; in temperate 



* Probably, T. secedens, Walk. (Plate VII., Fig. 54), or T. socicdis, Walk. (Plate 

 VIII., Fig. 57). E. E. A. 



t T. gabonensis (garonensis), Macq., is a synonym of T. secedens, Walk. E. E. A. 

 J T. nigrohirtus, Ricardo = T. socialia, Walk. E. E. A. 



