INJURIOUS INSECTS. 261 



color is most observed ; but varies from that to amber or honey- 

 yellow, lemon-yellow, and even to a cream-color. The specimens 

 already spoken of as having been rasied in dried earth, are all quite 

 pale ; and it would hence appear as though these lighter colored 

 varieties were caused by unfavorable circumstances in which the 

 insect had been placed when in its larva state. 



The spotted-winged wiieat-fly. 



Another species of Cecidomyia ( Plate 5, 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 tritici in form 

 and coloring, having like it an orange-red body, hyaline wings, pale 

 yellowish- while legs, and twelve joints to the antenna?, identical 

 with those of the tritici in their details. It is, however, readily dis- 

 tinguished 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. 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 seven 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-raedial. 

 Another spot occupies the apex of the wing, at the tip of the post- 

 costal nerve. Three others are based upon the inner margin, re- 

 spectively at the apex of the medial and anal nervures, and at the 

 axilla or base of the anal cell. The seventh 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 

 jg« 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. 

 j.ji| The species under consideration is farther distinguished from the 

 ijji tritici, by invariably having the base of the abdomen, on its upper 

 , (1,1 aide, of a brown or blackish color. The thorax is often of a darker 



