52 



pressed transverse lines, whereby it is divided into ten or twelve 

 segments of equal length, except at the ends where it is difficult to 

 definitelv distinguish them. It is of a rich yellow color varying in 

 different individuals from lemon to orange-yellow, and usually a 

 small greenish or blackish cloud is seen placed lengthwise in the 

 middle of the body on its under side, which is evidently caused by 

 internal alimentary matter. 



The moving larva is of a more elongated and elliptic form, taper- 

 ing to an acute point at its fore end and much more blunt behind. 

 Thirteen segments are now plainly to be seen. Of these the three 

 first and the last have a smooth surface and are whitish and semi- 

 transparent, only the nine intervening ones being yellow and with 

 their surface granulated. Each segment is fringed at its end with a 

 row of small hairs like eyelashes, which are continued along the 

 whole length of the edge. The head is conical, longer than 

 broad, tapering to an acute point in front, and has a depression on 

 each side near the middle where is inserted a short thread-like pro- 

 cess, forming with its fellow a pair of horns, which are articulated 

 at their bases. The last segment is cut off transversely in a straight 

 line ; but as the worm crawls, when it draws the hind part of its 

 body forward with each step it takes, this hind end becomes strongly 

 concave. When the worm is dry and endeavoring to crawl on a dry 

 surface, this end of its body becomes wholly different. It is then 

 strongly concave, its angles acute and tooth-like, with two similar 

 teeth between them which may be of the same size or retracted, 

 showing their points only. On each side of this last segment a 

 rounded tubercle is sometimes protruded from beneath, bearing a 

 conical point and • resembling a proleg. Under the same circum- 

 stances the head is wholly retracted, leaving only the ends of its 

 horns visible. 



Fiiva. — The cocoons in which the larvfe enclose themselves resemble 

 little round grains smaller than a mustard seed. When coated 

 with dirt, as they usually are, it is almost impossible to discover 

 these cocoons even with the aid of a magnifying glass. The naked 

 larvae that are sometimes found in the earth in the spring are 

 doubtless those which remained in the wheat after its harvesting. 



Imago. — The following remarks condensed from Fitch's Eeport 

 will constitute a sufficient description of the imago to enable the 

 intelligent observer to recognize it, especially when taken in con- 

 nection with the figures, copied on a larger scale from Fitch's plate. 



The individuals of this species differ so widely as to color, size, 

 and perfection of organs and members, that no study of these 

 points will enable one to distinguish this fly from other species 

 when specimens are gathered in other situations than on wheat. 

 We can then recognize it only when it shows the following essential 

 characters : 



The body nearly one-tenth of an inch long, bright orange or 

 lemon-yellow, and tarnished or slightly smoky on the back, forward 

 of _ the wings ; the wings clear and glassy and having a small cross 

 vein near their base ; the antennae about as long as the body and 

 composed of twelve oblong joints which are narrower in their 

 middles and separated by short pedicels. 



