THE SYRPHIDAF, OF OHIO 53 



Tip of posterior appendage nicely rounded off, smooth, the spiracles not eleva- 

 ted, and not separated by perceptible spurs. Tubes not at all divergent. 

 (PI. V, Figs. 72-73) Sphaerophoria cylindrica 



8. Larvae with the entire dorsal surface covered with short spines (scarcely visible 



without a hand-lens), black, or sometimes light in color and then not 



prominent 9 



Integument of the larvae bare except for the segmental spines 13 



9. Segmental spines conspicuous or raised on prominent, fleshy or spiny, conical 



projections easily seen b}* the naked eye 10 



Segmental spines not prominent and not raised on conspicuous conical project- 

 ions; sometimes hard to distinguish from the integumental spines 12 



10. All of these conical projections and their spines, on the dorsal side of the body, 



of nearly equal size; the inter-spiracular spaces on the breathing tubes 



with lamellate upright plates. (PI. I, Fig. 5) Didea fasciata 



The dorsal spines (ones next the median pair) in the principal segments much 

 reduced in size; the inter-spiracular spaces with short, spur-like proces- 

 ses, the median dorsal one long and prominent 11 



11. Posterior respiratory appendage broader than long. (PI. Ill, F'ig. 25) 



Paragus bicolor 



Posterior respiratory appendage considerably longer than broad. (PI. Ill, 

 Fig. 33 ) Paragus tibialis 



12. Integumental .spines black; inter-spiracular spaces with short, stout, black spurs. 



( PI. IV, Figs. 46-49) Syrphus americanus 



Intergumental spines light yellow; inter spiraculer spaces with long slender 

 hairs. (PI. VI, Figs. 94-95) The Cock's-Comb-Gall Syrphus-FIy 



13. Posterior respiratory appendage longer than broad. (PI. VI, I'igs. 84-87) 



Syrphus xanthostomus 



Posterior respiratory appendage broader than long. (PI. II, Fig. 13) 

 Syrphus torvus 



Paragus bicolor Fabricious 



(Plate III, P'igs. 21 to 30.) 



For a ftill account of the metamorphoses and life history of this 

 species .see the O///^ A^a/7^ra/z.y/, Vol. XII, No. i, pp. 397-401, Plate i, 

 Nov., 191 1, from which article the following sj-nopsis is written. 



Larva — Length about 8 mm. Color yellowish-brown, varied with black, brick-red 

 and drab. Integumental vestiture wanting. In segments 6-1 1, inclusive, the promi- 

 nences on which the dorsal spine.s are situated are only about one-sixth as large as 

 those prominences which bear the median, dorso-lateral, and lateral segmental spines. 

 In the fourth and fifth segments these are all of about equal size (See Fig. 21 ). The 

 mouth-parts (Fig. 23) consist of the beak-like jaws and four pairs of booklets. 

 Posterior respiratory appendage 0.25 to 0.4 mm. long, 0.25 to 0.3 mm. broad. Spira- 

 cles well elevated, noticeably curved in their extent. Inter-spiracular .'opines incon- 

 spicuous, dorsal spiracular one large, spoon-shaped, broad dorso-ventrally, narrower 

 from side to side, concave laterad. Eggs, larva and pupae taken from curled dock, 



