No. 105.] 281 



DESCRIPTION OF THE CLEAR-WINGED WHEAT-FLY. 

 Cecidomyia Tritici. — Kirby. 



The importance of full and accurate descriptions of every one of 

 the several parts of a natural object, in order that it may be identified 

 with certainty, is strikingly illustrated in the present species. For 

 some years it has been supposed to be identical with the English 

 wheat-fly ; but those who are aware of the large number of both plants 

 and animals in Europe, that have analogous representatives in this 

 country so closely resembling them as to have been in many instan- 

 ces for a long time considered identical even by accurate and experi- 

 enced observers, could not but entertain doubts upon this point; and 

 with the fifteen or twenty characters of this insect which could be 

 gathered from different sources, I could still only say that our wheat- 

 fly was probably the Tritici of Mr. Kirby, some of its prominent pecu- 

 liarities seeming even to conflict with the descriptions given of that 

 species. For instance, all that we could gather respecting the form 

 of the joints of the antennae, was, that they were " momVi/brmy'' 

 and Messrs. Kirby and Spence, in their "Introduction to Entomology," 

 define this term to mean " oval or globular joints, like a necklace of 

 beads." Now the joints of the antennae in our insect are oblong, 

 and each has a marked contraction in its middle, thus approaching to 

 an hourglass shape, a form the very reverse of" oval" or" globular." 

 It was not until I saw the excellent figures and descriptions of Mr. 

 Curtis, that I became well assured that our species was identical with 

 the European. 



The common reader will get the most clear and definite idea of the 

 appearance of the wheat-fly, by being told that it looks almost exactly 

 like the wheat-worm with wings and legs added to it. These mem- 

 bers, however, are so very small as to be scarcely recognized by the 

 naked eyes, except when they are fixed intently upon the object. 



The HEAD of the female Cecidomyia Tritici (Plate, fig. 1) is of an 

 orbiculate or flattened-globular form, with the eyes forming its peri- 

 phery. These are large, occupying full two-thirds of the entire head. 

 They are of a deep black color, and are separated from each other on 

 the top of the head only by a slight and almost imperceptible clefty 

 so that when viewed in front they appear like a continuous broad 



