2g8 [September. 



of Africa, not very much is added to the observations recorded in Neave's 

 earlier paper in the same periodical (Vol.3, 1912, pp. 279 seq.). But concerning 

 the earlier stages there is much of importance. Thus many egg-masses of 

 Tabanus corax were found on reeds and grasses overhanging mud. During 

 oviposition the female of this species is not easily disturbed, and reed, eggs and 

 fiy may sometimes be removed bodily without the latter ceasing her operations. 

 These egg-masses are of the usual Tabanid type, all the spindle-shaped eggs 

 lying with their long axes in the same direction. They are covered with a 

 cement which seems to be very waterproof and insoluble, as on one occasion 

 some larvae succeeded in hatching from an egg-mass which had been in 70 % 

 alcohol for two days. [This description of the egg-masses of T. corax recalls 

 the descriptions and figures of those of two other species, T. taeniola and 

 T. ditaeniatus, pviblished by H. H. King in the same volume, part 3, p. 247, 

 Dec. 1914]. In T. corax the process of hatching takes place with svirprising 

 suddenness. The egg-mass splits longitudinally down the middle line, and the 

 little larvae emerge almost simultaneously, forming a big semi-viscous drop, 

 which falls bodily from the reeds into the water or mud below.* 



Neave found and bred larvae of various species of Chrysops, Haemato- 

 pota, and Tabanus. They live in the mud on the banks and in the backwaters 

 of rivers, or in isolated pools in the beds of dried-up streams. Those of one 

 species of Tahayius are mentioned as being more usually found in the water 

 itself among the roots of floating plants. The young larvae, after liatching, at 

 first grow very slowly, and sometimes take six months to become full-grown. 

 They then go through a resting-period, lying buried in mud or sand, sometimes 

 at a considerable depth. In contrast to this long larval life the pupal period 

 is short, from 10 to 18 days onlj'. It appears that in this part of Africa the 

 Tabanidae have only one brood in the year. But even in larvae from the same 

 batch of eggs the rate of growth may be extremely variable, and adults may 

 thus emerge from pupae at irregular intervals over a long period. 



The writer describes his experiences in breeding the larvae. They were 

 kept in clay basins of various sizes, containing mud or sand, and placed separ- 

 ately under cages made of mosquito-netting. One difficulty arises from the 

 great activity of the older larvae, which can travel for considerable distances 

 over perfectly dry surfaces; thus they are liable to leave their wet mud and 

 to wander, getting lost, or mixed with those of other species, which, if the latter 

 be smaller or weaker, they will readily destroy. The new-hatched larvae are more 

 active than older ones, and swim more freely in water, lashing themselves along its 

 surface. Half- to full-grown larvae were fed, in the case of smaller kinds, largely 

 on immature Muscid larvae ; in the case of larger species, on molluscs, fish-fry, or 

 freshly killed tadpoles. Most species seem to be somewhat cannibalistic during 

 part of their existence, but usually lose this habit as they approach maturity. 

 The more mature larvae are principally nocturnal. When nearly matiu-e they 

 generally lie biiried head downwards, with their siphons just projecting above 



* This recalls an analogous, but not identical, plienomcnon in certain Tricluyptira which lay 

 their eggs in masses of jcllj'-like spawn on the leaves of trees, etc., overhanging water. In some 

 cases the larvae hatch from the eggs while still in this situation. When moistened by rain the 

 jelly swells, and tlie spawn-masses flow slowly to the tips of the leaves and drop into the water 

 beneath (see Wesenberg-L\ind, Intern. Rev. Hj'drob. Hydrogr., 1, 19u8, p. 869). 



