212 
Herrick also states that a second parasite, very similar to the 
Semiotellus destructor, “but with mere rudiments, is sometimes evolved 
from the pupae of the Hessian-fly. 1 am in doubt whether it should 
be considered a distinct species or only a variety.” 
A third parasite was reared by Herrick in Connecticut. It is an 
insect of the tribe Chalcidice, whose genus he did not determine. 
Its habits were like those of Semiotellus, and wingless females of this 
species were also found. 
A fourth parasite, noticed by Herrick, belongs to Latreille’s tribe 
Oxyuri, but the genus was not determined. In habits it agreed with 
the foregoing parasites, but it was evolved later in the year. Herrick 
adds that all the parasites mentioned “are likewise evolved in the 
spring from the Hessian-tiy pupse of the summer previous.” 
The fifth parasite has quite different habits. It lays its eggs in 
those of the Hessian-fly. Herrick, its first discoverer, thus speaks 
of it: 
“The insect is abundant in the autumn. I first saw it September 
23, 1833, in the act of depositing its eggs in the eggs of the Hessian- 
fly. From subsequent observations it appears that four or five eggs 
are laid in a single egg of the Hessian-fly. The latter egg hatches, 
and the animal advances to the pupa state as usual, but from the 
puparium no Hessian-fly ever comes forth. This parasite forms 
within the puparium a silky cocoon of a brownish color.” 
It is probable that it is the species first discovered by Herrick in 
Connecticut which Professor Cook has detected ovipositing in the 
eggs of the Hessian-fly. 
“It is black and looks not unlike a tiny gnat. The female feels 
for the eggs with her antennae, and when found intrudes the fatal 
egg, which, I find, takes three-fourths of a minute; full three times 
as long as it takes the Hessian-fly. The little parasite is much 
longer, too, in finding the eggs than is the fly in laying them. I find 
that each egg receives one, two or three of the parasite’s eggs. The 
eggs of these latter are tardy in hatching, so that the larva of the 
parasite may feed on the maggot of the Hessian-fly, not her eggs. 
These pupate in the puparium of the fly.” 
Platygaster error, Fitch?—Having received one of these egg-para¬ 
sites from Professor Cook, I find it to be so much like the Platygcis- 
ter error of Fitch (Fig. 1) that I refer it to that species, though with 
a doubt. This is probably also the parasite referred to by Mr. Herrick. 
It is shining black; the head is finely punctured, rounded, and 
slightly broader than long, being about as w r ide as the thorax. 
The antennae are about as long as the head and thorax; they are 
slender, but apparently a little stouter than in P. error, the penul¬ 
timate joints being a little broader and squarer than he represents 
(and they are very different from Platygaster tivulce), these joints 
not being “twice as long as thick,” but only £ to £ longer*; 
the terminal joint is long, oval, not so wide as those just be- 
* Sixth report on the noxious and other inserts of the State of New York, by Asa Fitch, 
M. D., PL 1, fig. 4, a, b. The figure is from Packard’s Guide to the Study of Insects. 
