Miscellaneous. 255 
fact that many of the skins of 7’yphlocyba presented a sort of appen- 
dage inserted at the upper part of the abdomen, and at the first 
glance producing an appearance as if the abdomen had been bifur- 
cated from its origin. 
This year, towards the end of June, the horse-chestnuts were 
again covered with Typhlocybe, and I was able to convince myself 
that we had to donot with an Entomophthorean but with an animal 
parasite, a Hymenopterous larva the mode of life of which is very 
remarkable. Almost all the Z'yphlocybe collected on the trunks of 
the trees bear, either to the right or left of the abdomen, a sac, of 
which the length and breadth are equal, or nearly so, to those of 
the abdomen itself. Concealed beneath the wings of the Homo- 
pteran, the flight of which it scarcely affects, this sac is inserted in 
the dorsal part of the second somite of the abdomen. A chitinous 
thickening in the shape of a V, or, rather, of a reversed circumflex 
accent, marks on the dorsal surface the point of insertion of the 
sac. In the interior we find a Hymenopterous larva bent upon 
itself ventrally in such a way that the mouth and the posterior 
extremity of the body meet towards the point of suspension. The 
two parts of the larva are separated from each other by a longitu- 
dinal partition which divides the sac into two portions in communi- 
cation at the two ends. A narrow fissure, the margins and the pos- 
terior part of which are tinged with a blackish pigment, starts from 
the point of the chitinous V and extends longitudinally for a dis- 
tance equal to the length of a somite of the Zyphlocyba. When the 
larva is mature this fissure is extended to the free extremity of the 
sac, and by means of this kind of dehiscence the parasite is set free 
and falls either into the crevices of the bark or to the ground, where 
it speedily becomes transformed into a pupa within a coarse case, 
like that of some Braconidee. 
The larva greatly resembles that of the Torymide and especially 
of the genus Misocampus. Upon each segment it bears a transverse 
row of long stiff hairs; the mandibles are well developed. The 
digestive canal is rudimentary and there is no anus; the fatty bodies 
are very voluminous and filled with rectangular crystals. belonging 
to the right prismatic system with a rectangular base. In a few 
days I hope to obtain the perfect insect and thus to arrive at a more 
precise determination of the parasite. But it seemed to me to be 
useful at once to call attention to this first-known example of a true 
animal-gall produced on the exterior of an Arthropod by another 
Arthropod. The sac of the Typhlocyba is, in fact, the extreme case 
of a series of deformations, such as those caused in certain Hyme- 
noptera by Stylops, or in the Decapod Crustacea by the Bopyride. 
It may also be compared with the sacs also produced by hyper- 
plasty of the cuticular hypodermis, but in the interior of the host, 
by the Tachinide (Ocyptera and Masicera) either in Heteroptera or 
in Coleoptera, or, further, to the sac in which the Entoniscidz live. 
It is evident that the Typhlocybe were infested in the pupa- or even 
in the larva-state, and it would be very interesting to follow the 
development of the sac step by step. The physiological effects pro- 
