THE BIONOMICS OF AUSTRALIAN TABANIDAE. 



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and fifth tergites are similar, except that the bristles are stouter and there are about 

 eight long bristles on each. On the sixth and seventh tergites the bristles are fewer 

 and stouter than on the preceding ones. On the pleura they are arranged roughly 

 in two rows, those in front being much shorter and fewer than those behind. Sternites 

 2-7 are armed similarly to their corresponding pleurites. On the anterior half of each 

 tergite there are five or six small dark-coloured depressions, the foremost being 

 nearest the pleura and the hindmost nearest the median line. Behind the anterior 

 margin of each segment and parallel with it there is another row of three or four 

 similar depressions on either side of the median line. The anterior two-thirds of each 

 tergite, pleurite and sternite are distinctly marked with transverse striae ; posterior 

 to the bristles these striae are less distinct or absent and the whole surface is punctate. 



Silvius notatus, Ric, anterior end of adult larva. 



Fig. 20. Silvius notatus, posterior end of adult larva. 



The terminal segment is deeply rugose, the two upper projecting spurs or bristles 

 are parallel along their inner margins in the female and divergent in the male ; the 

 middle pair is much larger than the upper and lower and projects laterally. The 

 anal tubercle of the male is very large and deeply furrowed ; in front it is bounded 

 by a continuous fringe of bristles, four or five comparatively small ones in the middle 

 and a group of four or five very stout ones on each side, similar to but larger than 



