33^ The Ohio Naturalist. [Vol. XI, No. 7, 



dorsal line crown the summits of prominent conical projections 

 which, like the rest of the dorsum, are close-set with short radiating 

 black bristles. The second of these projections from the middle 

 line on each side is about one-third as large as the first and situated 

 on the succeeding fold. These transverse folds are continued 

 laterally into distinct V-shaped prominences which with those of 

 other segments fonn a zig-zag longitudinal carina along each side 

 of the body. The third spine from the middle-line on each side 

 is situated at the apex of this V; the fourth at the apex of a sim- 

 ilar, underlying lateral cone or V; in front of which a small vent- 

 rall3^-projecting fold fonns two smaller spiny prominences bear- 

 ing the fifth and sixth bristles. These fomi the lateral borders of 

 the larva and give to it a \'ery irregular outline of sharp angular 

 projections. 



On the ventral part of the first segment are situated the inouth- 

 parts and dorsal to these the antennae. The mouth-parts consist 

 of two jaw-like pieces working longitudinalh^ and at the sides of 

 these three pairs of mouth-hooks adapted to work transversely 

 (Fig. 3.) The jaws are continued internally into a tube-like 

 oesophagus or gullet. All the parts are black and fimily chitinised. 

 The antennae are ver}- small consisting of a single fleshy joint 

 with two minute rounded segments side by side at its apex. 

 Surrounding these parts are a dozen or more small sensory papillae. 



In the middle of the third segment is a pair of anterior spiracles. 

 These are light brown, conical, with a semi-circular slit near the 

 apex (Fig. 4). 



On the anterior part of the dorsum of the last segment is sit- 

 uated the posterior breathing organ (Figs. 2,b;5). This consists of 

 two closely apposed, short, cylindrical breathing-tubes, united 

 along the middle line, slightly divergent at the tip. They are 

 hard, black, finnly chitinised structures, each with three slit-like 

 spiracles raised on radiating carinae. ilnteriorly near the middle 

 line each is inarked by a smooth circular plate; and the surface of 

 the appendages between the spiracles bears several sharp irregular 

 ridges. The alimentar\' canal opens ventrally on the last segment. 



The integument of these larvae is exceedingly tough but trans- 

 parent. The entire dorsal and lateral surfaces are beset with 

 numerous, minute, short black bristles. The ventrum is bare. 

 Along the mid-dorsal line for the greater part of its length the 

 dorsal blood-vessel is visible through the body-wall. It is a 

 poorly-defined, dark line with five or six lateral expansions. 



This fl}' is only tolerably common about Columbus. I was 

 able to find the young fairly common in the autumn of 1909; but 

 they were rare in 1910, owing perhaps to the greater scarcity of 

 their food the latter season. From the observations made it is 

 probable that the larvae of the autumn generation of this fly do 

 not appear before the last week in September or the first of Octo- 



