80 
FIRST ANNUAL REPORT OF THE 
If, therefore, we allow that this Plum Moth of mine is a Guest in the case of the two 
galls, which, as I have shown, it inhabits, it would seem to be most probable that it is 
also a Guest whenever it inhabits the Black-knot -and the Plum. In other words, it does 
not attack sound Black-knot and sound Plums, but only such as have been already 
preyed on and bored by the Curculio, and where consequently an opening has already 
been made lor its operations. Practically, this question is of considerable import¬ 
ance. For, if the Plum Moth does really attack perfectly sound plums, then it is as 
much to be dreaded as the Curculio. If, on ihe contrary, it only gathers up the crumbs 
that fall from the table of the Curculio, then it is absolutely harmless. For no fruit¬ 
grower would give one cent for a whole orchard of plums, every one of which was stung 
by the Curculio. The general subject of Guest-flies and Guest-moths, has been already 
treated of at some considerable length. (Above, pp. 17—18.) 
I have bred another species of small moth, very closely allied to the Plum Moth, from 
Black-knot; and Harris long ago noticed Lepidopterous larvae in Black-knot, which he 
originally mistook for those of the Peach Borer (sEgeria exitiosa , Say ;) though he sub¬ 
sequently corrected this error, and stated them to be “ the naked caterpillars of a 
minute moth.”* In all probability, these caterpillars, which Harris found in Black-knot, 
would have produced some one or both of the two species of Moths which I have bred 
therefrom, namely, the Plum Moth and an undescribed species. Although these larvae 
had long been noticed by entomologists in Black-knot, yet nobody, as it seems, had 
ever raised them to the mature state, until I succeeded in doing so. 
As I have already shown (p. 70,) the so-called “ Curculio Parasite ” of Dr. Fitch preys, 
in all probability, not upon the larva of the Curculio, as Dr. Fitch erroneously supposed, 
but upon that of the Plum Moth. I bred a single female specimen of this pretty little 
Ichneumon-Ay on the 23d of August, from the same vase of plums from which I bred all 
my Plum Moths. 
The Plum Moth; Fig. 3. (Semasia prunivora, new species.) Ground-color of front-wing, black. The 
basal 14 irregularly covered with rust-red. so as to leave only a few black markings. On the costa and 
rather more than Y z of the way to the apex of the wing, a pair of streaks obliquely directed toward the 
posterior angle of the wing; f the inner streak of the pair is on its extreme costal end clear white, else¬ 
where pale steel-blue, and extends nearly to the disk of the wing, where it almost unites with a sub' 
quadrangular pale steel-blue blotch, which is usually seen there without difficulty, though It is occasion¬ 
ally subobsolete; the outer streak of the pair is only half as long as the inner one, towards which it 
converges very slightly without actually uniting with it, and is colored in the same manner. Further 
along on the costa, and not quite % of the way to the apex of the wing, there is another such pair of 
streaks, parallel with the first pair and similarly colored, the inner one of which, when it has become 
as long as the inner one of the other pair, sweeps in a gradual curve round the disk of the wing, till it 
almost attains the inner margin a little way from its tip ; while the outer streak of the two is so very 
short, that the steel-blue part of it is subobsolete and can only be seen in certain lights. Beyond this 
second pair of streaks, and rather more than % of the way along the costa to the apex of the wing, is 
another streak, parallel with all the others and similarly colored, which strikes the outer margin about 
Y °f the way from the apical to the posterior angle, where it terminates in a pale streak in the fringe. 
* Compare Harris’s Injur. Insects first edition, p. 352, and last edition, p. 80. A writer in the Amer. Journ. 
Horticulture (Yol. II. p. 34.) has reiterated Harris’s original error. 
f In the figure this pair of streaks is erroneously engraved as being rather closer to the second pair of 
streaks, and rather further apart from each other, than is the case in the natural wing. And the same 
observation applies to the second pair of streaks as regards its distance from the third group of streaks, 
which consists, not of 2, but of 3. 
