26 



quite common throughout the state, it seldom becomes numerous enough, 

 except in restricted localities, to do serious damage. 



BIBLIOGRAPHY. 



1891, Riley and Howard, Insect Life, 4:94. 

 1891, Schwarz, Proc. Ent. Soc. Wash., 2:76. 

 "1893, Hopkins, Bui. 32, W, Va. Agri. Exp. Sta., p. 204, No. 217. 

 1899, Smith' 27th Ann. Rept. N. J. State Bd. Agri., p. 343. 

 1904, Swezey, Unpublished Notes. Div. N. & O. Insp. Ohio Dept. 



Agri. 



1905, Cotton, Ohio Nat., 5:346-348. 



THE YELLOW LOCUST MIDGE. 

 Cecidomyia robimae Hald. 

 Order, Diptera ; Family Cecidomyiidae. 



The gall-like thickenings on the edges of the black locust leaves pro- 

 duced by the larvae of this insect were very common in Ohio during the 

 summer of 1904. Usually but one gall is produced on a single leaflet, 

 "but two or more rnay be found, and it is not unusual to find several leaflets 

 of a leaf thus injured. 



The injury is caused by the female depositing her eggs near the edge 

 of the leaflet, which, on account of the irritation thus set up, folds inward 

 on the under side and becomes thickened and succulent, changing to a 

 pale yellowish-green color. From one to three very small white maggots, 

 varied more or less with orange yellow, develop within each of these 

 cavities. The larvae when mature descend into the ground and transform 

 to the pupa state, the adults appearing in about ten days. 



"The midge which develops from the larva is a pale orange color, 

 with the sides of its thorax and often three oval stripes on the back and 

 wings, dusky; antennae blackish, and of fourteen joints in the females, 

 twenty-four in the males; its length .12 inch." (Fitch & Haldeman). 



The injury produced by this insect is most evident during July and 

 August, but that the insect is present much earlier in the season is at- 

 tested by the writer's finding two leaflets showing the characteristic 

 thickened and rolled edges on May 15th, 1905, at Columbus. 



REMEDIES. 



No remedy can be suggested that is at all practical, except on a very 

 small scale. Where only one or two small trees are badly damaged by 

 tl^is insect, the injured leaflets may be picked oflf by hand and destroyed. 



