No. 105.] S83 



diameter. It is of an ovate form, often conspicuously attenuated 

 towards its tip, (as represented, fig. 1.) whence the two valvular sheaths 

 of the ovipositor are seen more or less exserted, and sometimes the 

 apex of the ovipositor itself projecting between them like a fine slen- 

 der thread. According to Mr. Curtis, by a slight pressure on the 

 abdomen of the living insect, the ovipositor (Plate fig. /) can be 

 made to protrude, and may then be drawn out to nearly thrice the 

 length of the body. 



The WINGS are hyaline and colorless, appearing like thin plates 

 of glass or mica, but reflecting the tints of the rainbow, particularly 

 the violet, when viewed in certain directions. Their margins are 

 densely ciliated with longish hairs, and their surface is covered with 

 minute pubescence. The mediastinal or suhmarginal nerve is but 

 slightly distant from the costal (marginal), and becomes confluent 

 with it rather forward of the middle of the exterior margin. From 

 its middle) it sends a small connecting nerve backward to the post-' 

 costal. The postcostaly which is the most conspicuous nervure of 

 the wing, runs direct, or with but an insensible curve, to the tip of 

 the wing. The medial is straight, and attains the inner margin at 

 about three-fourths of the distance from the base to the apex of the 

 wing. The anal runs nearly parallel with the inner margin, and, with 

 a very sudden curve from its direct course, joins the margin near 

 its middle. It gives off an obscure branch at its angle, which curves 

 outwards and backwards, joining the medial, or rather, seeming (if 

 the wing be moved so as to give a slightly different incidence to the 

 light) to be continued onward, parallel with and contiguous to the 

 medial nerve, till it attains the margin of the wing. The medial and 

 anal nerves are very slender, and are often invisible, except in a par- 

 ticular reflection of the light. The former, especially, can seldom be 

 distinctly traced, except towards its termination. These details of the 

 neuration of the wing apply equally well to all the species of Ceci- 

 domyia that have fallen under my observation, save only that they 

 are more distinctly traced in the others, particularly the larger species. 

 At rest (Plate fig. 6,) the wings are laid one upon the other, 

 reposing horizontally upon the back of the abdomen, and reaching 

 about a fourth of their length beyond it. 



The LEGS are whitish or very pale yellow, long and slender, of a 

 cylindrical form, and of nearly the same diameter through their entire 



