SOCIETY OF CENTRAL ILLINOIS. 243 



three pairs of legs and the fleshy prologs (ten in number) of a 

 caterpillar. From the peach borer, whose structure is similar, it 

 may be distinguished by its dusky color (the other being white), 

 its smaller size when full grown, and with a glass, by the hooks 

 on the prolegs. In the peach borer the ends of the soft, stump- 

 like prolegs are provided with small brown hooks arranged in 

 two opposite curves, discontinuous at their ends, each of a sin- 

 gle row; while in the new plum borer the corresponding hooks 

 form a complete ring, nearly covering the end of the leg. 



Kept in a breeding cage and supplied with chips and twigs of 

 plum-trees, our larvae spun small webs in which they passed the 

 winter. By May 3 a part of them had pupated ; and May 28 and 

 May 29 two winged moths emerged, all the others failing. 



These moths were small gray insects, the extended wings 

 measuring about eight-tenths of an inch. (The fore wings were 

 reddish behind (within), each with a large blackish gray patch 

 just beyond the middle. The hind wings were plain). 



Other moths of this species were taken several times at the 

 electric light in 1886, 1887 and 1888, the dates of their occur- 

 rence ranging from May 5 to August 24. The greater part, how- 

 ever, were collected in May and June, — and this is doubtless the 

 period of the greatest prevalence of the winged form. The 

 time and place of oviposition are unknown. 



In brief, the species is apparently single-brooded ; passes the 

 winter as a larva in the tree, pupates in May; emerges in May 

 and June, and may continue to lay its eggs through July and 

 August. 



Numerous experiments with insecticides for the destruction 

 of the larvae and the eggs are reported by Mr. Beckman, but all 

 without encouraging results. Unless the period of oviposition 

 is so long as to make preventive measures impracticable, it is 

 probable that the washes of soap, soda, carbolic acid and the 

 like, which protect the apple tree against the common borers, 

 may be used to advantage on the plum in summer as a defence 

 against this new enemy.* 



DESCRIPTION. 



Larva — The general appearance of this larva is that of a dusky, 

 somewhat hairy caterpillar, paler beneath, with reddish brown 

 head, darker in the middle, and a paler, variegated cervical 

 shield. 



Principal hairs conspicuously long and slender. The head is 

 brown, with a lateral black blotch behind the eyes, smooth, much 

 darker on the slightly depressed frontal area, this bordered by 

 depressed black sutures, outside which, at a little distance, is a 



* I have found mention of the larval habits of only two other species of the genus 

 (both exotic), one (E. cinerosella) living on wormwood (Artemisia) in Europe, and the 

 other (E. zellerella) bred from dates. 



