EXPLANATION OF FIGURE 12. 



A to J, inclusive, life stages of Syrphus knabi Shannon. 



A. Antero-ventral view of head of larva much enlarged; a, sensory pa- 



pillae; b, antenna; c, upper jaw; d, outer pair of mouth-hooks; e, 

 other mouth hooklets ; /, lower jaw; g, anterior spiracles or larval 

 respiratory cornua ; h, cephalo-pharyngeal framework within the 

 body. 



B. Lateral view of larva, X6 ; a, median segmental spines ; b, posterior 



respiratory organ. 



C. End view of anterior spiracle, highly magnified. 



D. Dorsal view of posterior respiratory organ, X 40 ; a, one of the three 



pairs of slit-like spiracles ; b, one of the inter-spiracular ridges ; c, 

 the median dorsal spiracular spur ; d, the circular plate. 



E. End view of the posterior respiratory organ, X 40. Lettering as in D. 



F. Outline of the puparium, dorsal view, ^ 3 ; a, posterior respiratory 



organ. 



G. Outline of the puparium from the side, X 3. 

 H. Scutellum and abdomen of adult ?, X 5. 



L Wing, X 5. 



J. Antenna of male. 



(Figures A to I redrawn from the Ohio Naturalist). 

 K. Abdomen of Xanthngraimiia divisa, X 10, to show arrangeinent of 

 the yellow markings. 



For other figures of Xanthograinuia divisa, see figures 8 

 and 9. 



