192 Cincinnati Society of Natural JIistor>/. 



mines, nov the surface of the leaves, from which they were bred. Ifviti- 

 foliella and ampelopsiella are forms of the same species, what shall we 

 say of P. vitigenella, Clem.? Its mine is always on the upjje^- surface of 

 o-rape leaves, and it has never been met with in those of ampelopsis. 

 It is very different from the mine of ampelopsiella, more like that 

 of vitifoliella, inasmuch as it wanders over the leaf regardless of the vena- 

 tion. But the character of the mine is very different from those both 

 of ampelopsiella and vitifoliella, inasmuch as it is barely perceptible, 

 like the track of a miuute snail; that is, it looks like an indistinct line 

 of slime, and not like a mine at all. The reason is that the larva 

 hardly burrows through the cuticle, and does not go down into the 

 parenchyma, and the track has a greenish, slimy look. The imago of 

 vitigenella is like that of vitifoliella in size and lustre, but it has the 

 basal streak and dorsal spot like ampelopsiella, only that they are not 

 so heavy, not being either so dark or so large as in that species. These 

 differences do not grade into each other; they are always distinct and 

 well marked. I have never seen a specimen (and I have seen hundreds, if 

 not thousands) which could not at once be referred, without hesitation, 

 to its appropriate form, or which showed the slightest indication of any 

 other form than its own, and I should not have the slightest hesitation 

 in considering them clearl}- distinct species, but for the facts above 

 stated that I get from the ampelopsiella mines the vitifoliella form as 

 frequentlv as I do the true ampelopsiella, and that Miss Muntfeldt and 

 Prof. Comstock inform me that they have bred the true ampelopsiella 

 from grape leaves. Still it is always the true ampelopsiella-^-the true 

 vitifolella, or the true vitigenella—uevev any thing between them. It 

 would not be any thing strange if a single species should feed on two 

 plants as closely related as ampelopsis and vitis. But that the same 

 mine in ampelopsis should give two distinct forms; that one of these 

 forms should always come from a different mine in grape leaves, and that 

 a still different form of mine from the same grape leaves should give 

 always an intermediate form, and yet that these three forms should al- 

 ways be distinct, with no obserA^ed tendency to variation in either, is 

 singular; and one's curiosity is still more piqued when he finds that a 

 mine more like that of vitigenella than either of the others; in a plant 

 as far removed, botanically, as the sweet gum {Liqudamber styraci- 

 Jlora) should always give a form indistinguishable from vitifoliella. 

 The vitigenella mine has not been known to produce any thing but 

 vitigenella, which is the intermediate form above alluded to. 



