THE WHEAT-STEM MAGGOT : ITS DESCRIPTION. 223 



The Fly Described and Illustrated. 



The insect, in its perfect state, is a lly, not unlike our common 

 house-fly {Musca domestica) in general shape, but of a more slender 

 form, smaller, and more delicately colored, and more conspicuously 

 marked. It belongs to the family of OscinidcB, which embraces several 

 genera, and quite a large number of American species, of which, by 

 far the larger j^roportion have been described by Dr. lioevv. 



This species was first described by Dr. Fitch, in the year 185G, in his 

 Second Report on the Insects of Neio York, as above cited, under the 

 nsLine o( Merotni/za Jniericana. The description given is as follows: 

 " It is 0.17 inch in length to the tips of its abdomen, and 0.20 inch to 



the end of the wings. It is yellowish- 

 white, with a black spot on the top of 

 its head, Avhich is continued backward 

 to the pedicel of the neck. Thorax 

 with three broad black stripes, ap- 

 proaching each other anteriorly but not 

 coming in contact, the middle stripe 

 r, .►. rri , . . n ., prolonged anteriorly to the pedicel of 



Fig. 6(. -The wheat-stem flv,JiEROMTZA -^ c j l 



Americana; enhirged to six diameters, the neck and posteriorly to the apCX 



of the scutel. Abdomen, with three broad, blackish stripes, which are 

 confluent posteriorly, and interrupted at each of the sutures. Tips of 

 the feet and veins of' the hyaline AVings blackish. Eyes bright green. 

 Antennae dusky on their upper side." The fly is shown in Fig. 67. 



Literature of the Species. 



No account of the habits or transformations of the insect is given by 

 Dr. Fitch, as they were unknown to him, the flies having merely been 

 taken by him in sweeping with a net over growing wheat. Its trans- 

 formations were first observed by Prof. Riley, and published by him in 

 the Eural Neio Yorker as above cited. 



In his First Report on the Insects of Missouri, 18G9, its transforma- 

 tions are also described, the larval depredations narrated, and the lar- 

 val, pupal, and perfect stages figured. 



Mr. Townend Glover in hiS Manuscnpt Xotes from my Journal — 

 Diptera, mentions the species and states: " The larvse live in the stem 

 of wheat, and injure it by gnawing tlie stalk from within, and by de- 

 vouring the substance immediately above the upper joint." 



It does not appear, from the above brief mention, that it had como 

 under the personal notice of the writer. Baron Osten Sacken has re- 

 corded the species in the two editions of his Catalogue of ihe^iptera 

 of North America, as the only known member of the genus, placing it 

 between the well-known genera Oscinis and Chlorops. Tlte specieg is 



