132 THE EARLY STAGES OF TABANID^ 



together forming an interrupted transverse row. These teeth are of unequal size 

 and vary in their relative size in different specimens. 



Tabanus pertinens Austen. — ^An African species, according to Neave 

 usually confined to comparatively low-lying country where the river 

 beds are of a sandy nature. In southern Nyasalalid it was found com- 

 mon on the Mwanza River, in the Shire Valley, as early as the end of 

 July, but did not occur on Mt. Mlanje, though a few specimens were 

 taken by Neave at some distance from the mountain. 



A pigmented larva (Plate 3, Fig. 54), which it was thought might 

 belong to this species, was taken in some numbers in the Shire River 

 in August, and in the Ruo River in October. It was found in both 

 cases in water amongst the roots of grasses or water plants, and 

 seems to prefer rivers with a sandy bottom and banks. The striking 

 larva is remarkable for the development of the dorsal prolegs, which 

 perhaps are associated with its comparatively free-swimming exist- 

 ence. The prolegs are also present immediately anterior to the anus. 



Tabanus quatuornotatus {quadrinotatus) Meigen. — ^Common in 

 Europe. This was the first species of tabanid in which the eggs and 

 the act of oviposition became known. The credit of the discovery is 

 due to Joseph Mann, Curator of the Imperial and Royal Zoological 

 Cabinet in Vienna, who, according to KoUar's report in 1854, during 

 a naturalist's trip to Carniola, Austria, in May and June, 1854, suc- 

 ceeded in observing in a damp meadow at Wippach the female of 

 Tabanus quatuornotatus in the act of oviposition. Mann's own words, 

 quoted by Kollar, are translated as follows: 



On June 25 at 11 a.m., I found a Tabanus just beginning to deposit eggs on a 

 grass blade; as it did not attempt to escape, I cut off the blade and took it home. 

 Towards 2 p.m. the Tabanus flew to the window; I at once looked at the grass 

 blade and found on it a cluster of eggs completed. These were wax-yellow at 

 first, later on they took on a grayish color, and two days afterwards they 

 appeared almost black. 



Mann later on found, in the field and also on other plants, several 

 egg masses similar to the first, bringing them all to Vienna. 



By this discovery it was known for the first time that the Tabanus 

 does not deposit the eggs on the ground where, according to Degeer, 

 the larva lived, but on plants; further, that the Tabanus does not 



