352 



as a variety of Phmierotoma tibialis Hald. The first named, which was 

 described and figured from specimens reared from A. si(/natus (Insect 

 Life, vol. a% p. 185) is an undoubted parasite of nigritiUH, and the 

 others are probably also parasites. A single specimen of each of the 

 latter was reared with no other host present. It is lather noticeable 

 that the parasites usually issued at the opposite end of the bud to that 

 used as a place of exit by the host. 



AN ORTALID FLY INJURING GROWING CEREALS. 



[^Chn'topsw aiiea Wied.) 



There is a rather common greenish-black fiy, with black banded 

 wings, as shown in the accompanying illustration, which ranges all 

 the way from Canada on the north to the Gulf of Mexico on the south, 

 occuiTiug also in Cuba and the Bermudas, which belongs to the family 

 Ortalida?, and is known as Ghcetopsis cenea. The larva of this insect 



Fig. 34. — Chcetopsis cenea. a, larva, with spiracular opeuing, highly ojaguiheil, at left; 6, puparimn; 

 ■fi, adult, enlarged (original). 



lives in a cavity which it forms within the stems of different cereal 

 plants, including wheat, oats, corn, and sugar-cane. It works, as a 

 general thing, near the base of the young growing plant, and either 

 kills it outright or interferes with its growth to such an extent that it 

 never perfectly matures. The eggs are laid in the leaf sheath, and the 

 larva transforms to pupa in the same position. 



This insect was first brought to the attention of this office in July, 

 1881, when larv;e found in a piece of sugar-cane, which had been dam- 

 aged by the sugar-cane beetle, Ligyrus rugiceps, were sent in by Mr. 

 W. T. Holmes, of Cypremont, La. Later it Was rather carefully studied 

 in its relation to the oat crop by Mr. W. B. Alwood, in June, 1886. 

 Mr. Alwood was then employed as an agent of the Division and was 

 stationed at Columbus, Ohio. The larva^ were found about the middle 

 ol June in an oat field, and had the effect of killing the blades at the 



