APR 1 8 
'The Ohio Naturalist, 
PUBLISHED BY 
The Biological Club of the Ohio State University. 
Volume XIII. 
MARCH, 1913. 
No. 5. 
library 
NEW YORK 
HOT AN 1C AL 
QAftBftM. 
TABLE OF CONTENTS. 
Metcalf -Life-Histories of Syrphidae 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 
McLeli.an— 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 89). 
Larva. 
Length about 10 mm. (8 to 11.5), width 3.75 to 4 mm., height 
2.5 to 3 mm. Fat, thick, grub-like, sluggish larvae, 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 papillae around 
the mouth-parts and antennae. The antennae 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 
Si 
