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mining the leaves throughout the summer, from June to 

 September, and often several may be found working to 

 gether on the same tree. Tlie moths themselves are 

 rarely seen, because of their minute size. They place 

 their lenticular eggs, usually one on a leaflet, and then 

 disappear. But the flattened grubs hatching from these 

 eggs bore into the leaf, eating away its substance 

 and detaching at the same time the epidermis, thus 

 producing blotches which at once attract attention. To- 

 wards fall one may see trees with most of the leaves ren- 

 dered by these miners so brown that they give to the 

 trees the appearance of having been killed. Examina- 

 tion of the leaves of locust trees at intervals during the 

 summer will show the presence of four distinct species, 

 three moths and one beetle, which may be recognized by 

 the character of the mine. The grubs are so small as to 

 be difficult of examination, except with a magnifier. 



1. One of the most abundant of the moths places its 

 eggs on the leaves early in June, and its young make a 

 large mine occupying much of the leaflets immediately 

 above the midrib. These mines usually have extensions 

 or lobes from the sides, so that their outline becomes 

 finally very irregular. Several broods appear each sea- 

 son. The technical name of this miner is Gracillarm 

 robiniella. 



2. The second species, also a moth {Lithocolletis robin- 

 iella), proves common in the latter part of summer, my 

 first record of its appearance being August 5. The ma- 

 jority of the mines of this species are on tlie under side 

 of leaflets, and are of a pure white color. They may be 

 at the margin of the leaflet or elsewhere, and the outline 

 is generally not irregular. The grubs make for them- 

 selves small lenticular silken cocoons in the mines when 

 ready to change, the moths emerging from them during 



