ACTING STATE ENTOMOLOGIST 
19 
The genus to which it beloi^gs is a rather extensive one, no less than seven U. S. species 
(not three as incorrectly stated by Dr. Fitch, N. Y. Rep. I. p. 255) having been described 
by a single author, Thos. Say; and moreover the species are difficult to distinguish from 
one another, owing to the monotonous uniformity of their coloration.* I think that 
my grape-inhabiting species is probably identical with the Fickle Midge ( Sciara [ molo- 
inconstans) of Dr. Fitch, which is described by him as making its appearance at 
the same unseasonable time of the year — the latter part of December—and as running 
about in the same fickle, rapid, restless manner as I have observed mine to do. Of this 
Guest-fly, from the same lot of about 50 infested grapes from which I had previously 
bred the Grape Curculio and the Guest-beetle, I obtained November 19th-29th, no less 
than 35 specimens ; and probably, owing to their lively movements, about as many more 
escaped out of the breeding vase, when from time to time I opened it in order to catch 
them. As to their habitually living in these infested grapes, the observations already 
made with regard to the Guest-beetle apply with two-fold force, inasmuch as they were 
about twice as numerous as the Guest-beetle. 
It is worthy of remark, as illustrating what I have called the “Unity of Habits|” in 
the same genus of insects, that another species of the same genus, the Apple Midge 
{Sciara \molobrus~\ mail , Fitch) was found by Dr. Fitch to be a Guest in apples infested 
by the common Apple-worm {Carpocapsa pomonella , Linnaeus), and to appear in the 
winged state at the same inclement period of the year as my Grape Mide, namely in 
February. 
Fruit-growers must observe carefully the important practical point, that none of 
these Guests do them any harm. It is the Grape Curculio, for example, that in the 
first instance attacks the berry ; and after the berry for all practical uses is ruined, the 
Guests merely pick up the stray crumbs that fall from the Curculio’s table, and clear 
away from olf the face of the earth decaying vegetable matter, that would otherwise 
become putrid, unwholesome and offensive. To make war upon the Guests would 
therefore be as irrational, as for a sheap-grower to shoot the turkey-buzzards that are 
feeding upon the dead carcasses of his sheep, and overlook the bloodthirsty curs that in 
the darkness of night had carried death and destruction among his flocks. 
Nothing is more common among young entomologists than to jump to the conclusion 
that, merely because they breed a certain insect from some vegetable organism which 
has manifestly been destroyed by insects, therefore the bred insect is the author of the 
mischief. No mode of reasoning can be more unsafe and unsound. The bred insect 
*Having found the descriptions of Say’s seven species and Fitch’s five species of this genus very unsat¬ 
isfactory, and being unable to separate into distinct species scores of specimens which I had captured at 
different times, though, by way of guide, I had, besides the “ Grape Midge,” considerable numbers of 
two distinct species which I had formerly bred from larvm found in decaying wood, I sent specimens of 
the “ Grape Midge ” to our great N. A. Dipterist, Baron Osten Sacken, with a request that he would, if 
possible, determine the species to which it rightfully belonged. For the benefit of young entomologists, 
I give his reply in this note, without making any alteration in my text. lie had previously expressed 
to me the same opinions with regard to the allied genus Ceratopogon, and I have myself published nearly 
the same views with reference to another allied genus, Cecidomyia. 
“ Your fly is certainly Sciara , but the species is indeterminable. I would not give anything for the 
determination even of a European Sciara. It is a difficult genus which has never been satisfactorily 
studied. The number of species seems to be very large, their coloring uniform, and their characteristic 
marks unknown. One does not know what to take hold of in describing such a species.” 
