300 WHEAT FLIES CHLOROPS AND OSCINIS. 



In the genus Chlorops, as the name will indicate to those who are 

 acquainted with the Greek language, the eyes are green. They 

 might hence be popularly named the green-eyed wheat-flies. 

 But as their scientific name Chlorops will be a more definite and 

 convenient designation it will be better to adopt it as the popular 

 name of these flies. Their bodies are commonly of a yellow 

 color, varied more or less with black in the different species. 

 One of these species was so abundant the latter part of June that 

 at almost every step in any of our wheat fields a dozen or more 

 of them could be seen. It may therefore be termed 



The common Chlorops, C. vulgaris, (plate 1, fig. 4, the short line to the left of 

 the figure indicating the natural length.) It measures 0.15 or a little less to the 

 end of its abdomen and from 0.18 to 0.20 to the end of its wings. It is of a pale 

 tawny yellow color, with a round black spot on the top of its head, and the tips of 

 its antenna? and of its feelers arc also black. It has two black bristles at the end 

 of the middle shanks, and one at the end of the forward ones, and rows of black 

 bristles upon the thorax. On the top of the head (fig. 4 a) are two pairs of bristles 

 inclining backward and two pairs inclining forward, the anterior pair of the latter 

 being shorter. The abdomen is oval, and in its normal state is of the same color 

 with the thorax; but from inclosed alimentary matter it becomes variously dis- 

 colored, often showing obscure brown or reddish spots. 



The feather-horned Chlorops, C. antcnnalis, is the same size as the preced- 

 ing, but with the abdomen commonly shorter. It is pale yellowish varied with tawny 

 and is whitish beneath. The antenna? are pale orange, their tips black, and the 

 bristle which arises from them, and which is simple in the other species, is here 

 feathered or plumose. On the top of the head is a black spot and the feelers are 

 also black. It is also clothed above with black bristles. The abdomen when dis- 

 tended with aliment is broad oval and of a dull livid or pale brown color, with the 

 sutures whitish. 



The genus Oscinis is distinguished from Chlorops by having 

 the coarse vein which forms the outer edge of the wing prolong- 

 ed around the tip of the wing to the end of the inner of the two 

 middle veins of the wing, at which point this marginal vein ab- 

 ruptly becomes slender, (see plate 1, fig. 5); whereas in the 

 genus Chlorops it is at the end of the outer middle vein that this 

 thick robust marginal vein terminates, (see fig. 4 of the same 

 plate). The species of Oscinis are further distinguished from 

 those of Chlorops by being of a smaller size and of black instead 

 of yellow colors. Several species of both these genera, in addi- 

 tion to those here presented were met with upon wheat, but I 

 defer a description of them to a future occasion. 



The shank-banded Oscinis, O. tibialis, (plate 1, fig. 5) is 0.08 in length to the 

 tip of its abdomen and 0.11 to the end of its wings. It is black, polished and 

 shining, its shanks and feet being pale dull yellow, the hind shanks having a broad 



