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66 
first annual report of the 
Naturalists have been puzzled for ages to designate satisfactorily what they mean by 
tiie term “ species,” and all kinds of loose and shadowy and intangible explanations of 
the term have been given; the latest discovery being that of an American refuter of 
Darwinism, flourishing in the great City of New York, who defines a “species” as a 
“specific form ;” which is much like explaining the term “ yellow ” by saying that 1 
means “ that which possesses yellowness.” Darwin himself maintains that species aie 
not essentially different from mere varieties. In their origin, I allow that they are the 
same ; for I believe with Darwin that every species originated from a variety of some 
pre-existing species. And I further allow that there is a transition period, during which 
i t is impossible to say whether a particular form is a variety or a species. But that does 
not prove that varieties and species are essentially ^distinguishable. Every man was 
originally a boy ; and there is a certain period during which it is difficult to say whether 
a particular individual is man or boy; but that does not prove that manhood is undis- 
tinguishable from boyhood. For myself, more than a year before I published on the 
subject of “ Phytophagic species,” I announced it as my opinion, that the meaning of 
the term “ distinct species” was simply “those that do not now in general mix sex¬ 
ually together, or, if geographically separated, would not do so, supposing them to be 
placed in juxtaposition;” and that “ the only valid practical criterion of specific dis¬ 
tinctness is the general non-existence, either actually ascertained or analogically 
inferred, of intermediate grades in the distinctive characters, whence we may reason¬ 
ably infer that the two supposed species are distinct.” ( Proceedings Entomological So¬ 
ciety Philadelphia , 1863, II., p. 220.) It is in this sense, and in this sense only, that I 
have ever used the term “ species ;” and to call such a definition an “ assumption ” 
seems to me much the same thing as saying that Euclid assumes a fact, when he defines 
a circle as a plane figure having all its external points equidistant from a given internal 
point. 
But to return from this tedious digression : —It has long been a puzzle to Naturalists, 
why the Plum Curculio should cut the well-known crescent-shaped slit in the fruit, and 
why a round hole w r ould not answer its purpose equally well. Harris and bitch and 
other authors tell us, that “it first makes a small, crescent-shaped incision with its 
snout in the skin of the plum, and then, turning round, inserts an egg in the wound.”* 
Misled by these authorities, and never having personally examined into the point, I 
copied their statements in my Paper on the Curculio. But Mr. 1 . C. Hill, oi Ohio, has 
since shown, that we have all of us been in the wrong, and that the Curculio first of all 
bores a round hole with her snout, “ not straight in, but slanting backwards, so that 
the cavity is just below the skin, then deposits her egg in the hole, and then cuts the 
usual crescent-slit in front of it, so as to undermine the egg and leave it in a kind of 
flap, formed by the little piece of the flesh of the fruit which she has undermined.” 
{Praci. Entomol. II. p. 115.) Mr. Hill very acutely suggests, that the object, of this 
complicated process is, “to wilt the piece around the egg and prevent the growing fruit 
from crushing it; ” and I have no doubt at all that this is the true explanation of the 
phenomenon. The same end is attained, as we shall see hereafter, but by a very differ¬ 
ent process, in the case of the Plum Gouger (Anthonomus prunicida , Walsh), an insect 
belonging to a widely distinct group of Snout-beetles. It may be added here, that the 
“ phytophagic species” of Curculio, that I bred from the green Butternut, makes just 
* gee Harris’s Injurious Insects, p. 76, aud pitch’s Address on the Curculio, p. 18. 
