The Ohio TSCaturalist, 



PUBLISHED BY 



The Biological Club of the Ohio State Uni'versity, 



Volume XIII. MARCH, 1913. No. 5. 



TABLE OF CONTENTS. 



Metcalf — Life-Histories of Syrpliidae V 81 



HiNE— Additions and Corrections to the Odonata of Ohio 94 



Williams— Carnivorous Plants of Ohio 97 



Claassen— Caloplaca Pyracea (Ach.) Th. Fr., a Crustaceous Lichen on the Sandstone 



Sidewalks of East Cleveland, Ohio 99 



McLellan— Meeting of the Biological Club 100 



LIFE-HISTORIES OF SYRPHIDAE V. 



C. L. Metcalf. 



Syrphus xanthostoma Williston. 

 The Pemphagus-Gall Syrphus-Fly. 



(Plate IV, Figs. 81 to S9). 



Larva. 



Length about 10 mm. (8 to 11.5), width 3.75 to 4 mm., height 

 2.5 to 3 mm. Fat, thick, grub-hke, sluggish larvee, elongate 

 oviform in outline, strongly arched dorsally (Fig. 82). Wrinkles 

 prominent, produced laterally into an irregular, dorso-lateral 

 carina; the ventral folds of the body in the principal segments 

 serve as very imperfect prolegs. General color very pale, pinkish- 

 yellow. Heart line not conspicuous. Skin bare, the segmental 

 bristles short and light in color, very inconspicuous. 



The jaws of the mouth-parts are unusually short, their width 

 at base equal to their length, the lower jaw the heavier. Mouth- 

 hooklets apparently three pairs: two near the jaws of which the 

 ventral pair is the heavier, the third pair lateral in position, 

 heaviest of all. There are a number of sensory papillce around 

 the mouth-parts and antenna. The antennas are small, situated 

 close together above the jaws, of the usual form (see Fig. 81). 



The prothoracic spiracles are slightly elevated, blunt, short, 

 horn-shaped as seen from the side (Fig. 81, g), the semi-circular 

 slit apparently guarded by six, blunt teeth, one of the median 

 ones emarginate or imperfectly divided (Fig. 83). The posterior 



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