No. 105.] 285 



been raised in dried earth ; are all quite pale ; and it would hence 

 appear as though these lighter colored varieties were caused by unfa- 

 vorable circumstances in which the insect had been placed when in its 

 larva state. 



THE SPOTTED WINGED WHEAT-FLY. 



CECIDOMYIA CEREALIS. 



Another species of Cecidomyia (Plate fig. 2,) as the reader has 

 been already informed, is frequently met with, associated with the 

 Tritici in fields of wheat. It is closely allied to the latter in form 

 and coloring, having like it an orange colored body, hyaline wings, 

 pale yellowish-white legs, and twelve joints to the antennse, identical 

 with those of the Tritici in their details. It is, however, readily 

 distinguished from the Tritici, as well as from all the other species of 

 this genus, with only two or three exceptions, by having spots upon 

 its wings. (Plate, fig. k.) These spots are so conspicuous as to 

 be recognized by the naked eye, even when the insect is flying. 

 They are of a pale black or smoky color, and bix in number on each 

 wing. Two, and these the most conspicuous from being commonly 

 of a deeper tint, are placed upon the outer margin ; one being at the 

 tip of the submarginal nerve, where it unites with the costal ; the 

 other, half way between this and the apex of the wing. Both these 

 spots reach across the costal cell, and often slightly into the externo- 

 medial. Another spot occupies the apex of the wing, at the tip of 

 the post-costal nerve. Two others are based upon the inner margin, 

 one at the apex of the middle nerve and mostly in the inner middle 

 cell, the other occupying the middle of the anal cell, but nowhere 

 touching the anal nerve. The sixth spot is upon the disk of the 

 wing, mostly in the outer middle cell, and is sometimes confluent 

 more or less with one or more of the marginal spots. The nerves, 

 when traversing these spots, are of a deeper black color than in other 

 parts of their course, as are also the hairs which proceed from them 

 into the fringed border of the wing. These spots are formed by a 

 pigment in the membrane of the wing, the fine pubescence upon 

 the surface being no more dense here than upon the other 

 parts. The species under consideration is farther distinguished 

 from the Tritici, by invariably having the base of the abdomen, on 

 its upper side, of a brown or blackish color. The last joints of the 



