534 The Ohio Naturalist. [Vol. XII, No. 8, 



In the field I have found eggs of this species on persimmon trees 

 (Diospyros virgin iaiia L), at the University Campus the last of 

 May, and on curled dock (Rumex crispus L.) at Lakeville, Ohio, 

 June 16-18. The eggs are deposited singly and laid fiat on the 

 surface of the leaf, twig, or flower. 



I know no way of distinguishing these eggs from those of related 

 Syrphidas except by the size, shape and the microscopic character- 

 istics of sculpturing described above ; these may prove insufficient 

 for specific separation when the eggs of more species are known. 



Larva. 



When just hatched (Fig. 65) the larvae have a length of 1.2 mm., 

 width 0.25 mm. They are irregular in outline, nearly cylindrical, 

 broadest near the middle; feeble and inactive. Color whitish, 

 with a yellowish or greenish tinge. The usual small, fleshy, 

 conical elevations are present, twelve to each segment, but the 

 segmental bristles were not discernible, apparently absent. The 

 posterior breathing appendages are rather prominent, longer than 

 in a young larva of S. americanus, and light in color like the rest of 

 the body. Their tips are, at first, rather remote from each other 

 though with subsequent growth and their greater elevation above 

 the general body surface they become contiguous. The two longi- 

 tudinal fat bodies are discernible as a white line on each side of the 

 dorsal blood-vessel which is more prominent in the posterior half 

 of the body. The skin is faintly wrinkled transversely. 



From this condition there seems to be a gradual growth until 

 the larva, when full-grown, has reached a length of about 8 mm., 

 width 2 mm., heigth 1.25 mm. It may then be described as 

 follows: Shape elongate oval, but much more pointed at the 

 anterior end when extended. The outline is somewhat irregular 

 due to folding and wrinkling of the skin. The posterior end is 

 rounding, truncate except for the projections of the posterior 

 breathing organ; (Fig. tj()). 



Color green, very similar to that of the cabbage leaf (on which 

 they occur commonly) with two longitudinal white stripes. This 

 color is due to colored visceral bodies which show through the 

 transparent skin. Along the mid-dorsal line for two-thirds the 

 length can be seen the narrow, dark, pulsating blood-vessel, its 

 prominence varying with different specimens. It is irregularly 

 limited at the sides by a narrow mass of greenish, fatty globules 

 changing gradually to whitish. This whitish adipose matter forms 

 the two prominent longitudinal white stripes, 0.2 or 0.3 mm. wide 

 and extending to within a few millimeters of either end where they 

 become much attenuated. The rest of the body, except the ap- 

 pendages is green, darker on the sides. The breathing tubes are 

 light brown, black at the tips where the spiracles are located. 



