54 THE EARLY STAGES OF TABANID^ 



"Antenna! sheaths not very thick at base, surpassing the marginal angulation 

 above them; carinated tubercles not prominent, lateral notches broad and shallow, 

 palpal sheaths indefinite, rather distant; setiferous tubercles scarcely darker; 

 ocellar tubercles replaced by pale dots. Rima of thoracic spiracles (Plate 13. 

 Fig. 157) strongly elevated from inner side, so that the flat top of the promi- 

 nence is nearly vertical, the upper edge of the rimal border forming a sharp carina 

 and its anterior extremity ending at the tip of the marginal extension in an acute 

 angle; the free lower edge is crossed by sharp ridges, giving it a serrate profile; 

 rima less curved at middle, more strongly at each end, scarcely hooked; 

 inner notch with radiating striations." 



"The abdominal fringes consist of a single row of pale spines on each segment, 

 rather long except dorsally on the second, where they are shorter and thicker. 

 The abdominal spiracular tubercles arise from a slight elevation, tapering from 

 a comparatively small base as far as middle, thence nearly cylindrical to 

 apex, which bears a subcircular rima; on the anterior slope a small transverse 

 groove, not longer than the rima; tubercle about as high as its basal diameter. 

 Last segment with six nearly equal terminal teeth, their points marking the 

 angles of a hexagon; slender, even constricted at base, twice as long as their 

 diameter near base. Lateral spines almost wanting; ventral fringe in front of 

 anal tubercle in male; a tuft of about five spines on each side in place of this fringe 

 in the female." 



Chrysops wellmani Austen. — An African species, which, according 

 to Neave, occurs in fair numbers near Mt. Mlanje, southern Nyasa- 

 land, from September to January. 



The larvae of this species (Plate 3, Fig. 50), differ strikingly from 

 any of the other Chrysops larvae seen by Neave, in their strong pig- 

 mentation. In the figure it is seen that while segments 1 to 3 are 

 free from pigmentation, segments 4 to 11 show the regular tabanid 

 pigmentation on the transverse circular ridges, leaving an area around 

 the prolegs free from pigment. There are no longitudinal stripes, but 

 on segment 11 there are two subdorsal dark spots (in addition to the 

 broad posterior band) , traces of which are also visible in the figure of 

 the syphon of Chrysops longicornis. 



The larvae were obtained in the beds of forested streams with those 

 of Chrysops longicornis and Chrysops magnifica, var. inornata, but 

 were much less common. They were found only between the middle 

 of October and the end of November. There is considerable differ- 

 ence in the hooks of the aster in the two sexes of this species, the 

 upper and lower hooks, especially the former, being much reduced 



