MUSCIDiE. 415 



the earlier varieties, seeming to have a particular fondness for 

 the old fashioned Summer, or Kigh-top Sweet. The larvae en- 

 ter the apple usually where it has been bored by the Apple- 

 worm (Carpocapsa) , not uncommonly through the crescent-like 

 puncture of the curculio, and sometimes through the calyx, 

 when it has not been troubled by other insects. Many of 

 them arrive at maturity in August, and the fly soon appears, 

 and successive generations of the maggots follow until cold 

 weather. I have frequently found the pupge in the bottom of 

 barrels in a cellar in the winter, and the flies appear in the 

 spring. In the early apples, the larvae work about in every 

 direction. If there are 

 several in an apple, they 

 make it unfit for use. 

 Apples that appear per- 

 fectly sound when taken 

 from the tree, will some- 

 times, if kept, be all alive 

 with them in a few Fig. 336. 



weeks." Other species are known to inhabit putrescent 

 vegetable matter, especially fruits. Mr. B. D. Walsh also des- 

 cribes in his "First Annual Eeport on the Noxious Insects of 

 Illinois," another apple fly, Trypeta pomonella Walsh, which 

 destroys stored apples, and has been found troublesome in va- 

 rious parts of the country. 



_, In England Oscinis granarius Curtis lives in the stems of 

 wheat. The Oscinis vastator Curtis does serious damage to 

 wheat and barley crops in England, by eating the base of the 

 stalk. The larvae are fully grown late in June, and a month 

 later, the fly appears. Their attacks are restrained by numer- 

 ous Pteromali, and a minute Proctotrupid (Sigalphus caudatus) 

 oviposits in the egg of the Oscinis. Other allied species in the 

 larva state cause the stems of wheat and barley to swell twice 

 their usual size, which disease is termed in England the gout. 

 The larvae of Chlorops lineata Fabr. in Europe, destroy the 

 central leaves and plant itself, the female laying her eggs on 

 the stems when the wheat begins to show the ear. In a fort- 

 night the eggs hatch, and the fly appears in September. Curtis 

 also states that CMorops Herpinii Guerin, attacks the ears of 



