EXPLANATION OF FIGURE 33. 



Syrphus torvus Loew. 

 o Adult male, natural size and enlarged. 



10 Larva, natural size and enlarged ; a, anterior spiracle ; b, posterior 

 spiracle. 



11 Antero-ventral view of head and mouth-parts much enlarged ; a and 

 b, upper and lower jaws partially separated; c, outer pair of mouth 

 hooks ; d and e, two inner pairs of mouth-hooklets ; f , antenna : g, 

 anterior spiracle ; h, sense papillae. 



12 Anterior spiracle of larva highly magnified. 



IS Posterior breathing appendages much enlarged ; a, one of the six 

 caudal spiracles. 



14 Puparium from above, natural size and enlarged ; a, posterior spira- 

 cles. 



15 Puparium from side showing line of cleavage for escape of adult. 



16 Head of female in profile. 



