114 THE EARLY STAGES OF TABANID^ 



While the Tipula appears in two generations, the life cycle of the 

 Tahanus comprises only one generation, which begins at the end of 

 spring of one year and is completed towards the middle or end of 

 spring of the following year. 



The larva of Tipula and those of Tahanus are, as del Guercio in- 

 sists, of the same dark gray color as the soil in which they live and re- 

 semble one another not only in shape but also in many of their organs, 

 including the mouth-parts, in such a way that there remains no 

 point of resemblance, even in this regard, between the larva of the 

 Tahanus of the rice field and that, for instance, of Tahanus autumnalis, 

 the larvas of which differ from it in every detail. 



The pupa, however, is figured by del Guercio (Plate 11, Fig. 123) 

 as the pupa of this Tahanus, for comparison with the tipulid pupa 

 (Plate 11, Fig. 122), and is in fact in every way a real Tahanus pupa, 

 except that on the figure no spiracles are visible, which were appar- 

 ently overlooked by the author in making the drawing. 



Del Guercio' s statement that the damage done by tipulids and 

 tabanids in the rice fields resulted in the destruction of the whole 

 cultivation, has probably to be corrected in that as far as any larvae, 

 the tipulids may possibly have been responsible for the damage; for 

 the tabanids, however, this is very unlikely, and, as long as del 

 Guercio has, in fact, made no observations whatever on the food of 

 his larvae, we are bound to assume that the Tahanus larvae, which 

 were apparently numerous, but of which we are still awaiting de- 

 scription, fed on the larvae of Tipula oleracea, and were in this in- 

 stance certainly not injurious. 



I wish here to call attention to the fact that Degeer has already 

 spoken of a great regemblance between tabanid and tipulid larvae; 

 in fact, before he knew that the larvae found by him were larvae of 

 Tahanus, he expected crane-flies to hatch. However, his descrip- 

 tion, the first one ever given of a Tahanus larva, establishes beyond 

 doubt the characteristics of these larvas by which they differ from 

 those of tipulids. 



Tahanus insignis Loew. — {Tahanus sharpei Aust.). An African 

 species, common in southern Nyasaland, near Mt. Mlanje, from No- 

 vember to March. 



