Miscellaneous. 479 
with his researches the T'yphlocybe of the horse-chestnut indicated 
in the former note as 7’. rosw, Linn., really belong to two distinct 
species, viz., 7’. hippocastani, J. Edw., and 7. Douglasi, J. Edw., 
which are equally common on the trees of the Luxembourg. These 
two species may be attacked by the two parasites here mentioned ; 
but the Aphelopus especially infests 7. hippocastani, while the 
Atelenevra almost always occurs in 7’. Douglasi. 
The females of 7’. hippocastani and 7’. Douglasi are very difficult to 
distinguish ; nevertheless in the latter the ovipositor is more robust 
and presents only a single curvature, while in 7’, hippocastani it is 
thinner and doubly curved in the form of ascimitar. In individuals 
of both species parasitized by Aphelopus the ovipositor is generally 
much reduced and incapable of penetration, but Atelenevra seems to 
have much less influence on the development of this organ. 
As regards the male genital armature, in 7’. Douglasi the penis is 
simple and the lateral pieces have the form of legs; parasitic castra- 
tion, whether by Aphelopus or Atelenevra, causes very slight modifiva- 
tions init. In 7. hippocastant the lateral pieces are simple and 
slender arcs, but the penis presents a very complex structure and 
terminates in a fork with eight branches of very elegant form. In 
the males parasitized by Atelenevra, and especially in those infested 
by Aphelopus, the penis undergoes considerable reductions; it has 
sometimes six, sometimes four, and sometimes only three branches. 
The specific character is thus greatly modified, and some of the forms 
might easily be confounded with 7. rose, Linn., or V. Lethierryi, 
J. Edw. 
Modifications of equal extent occur in certain singular organs, the 
existence of which in the males of Typhlocyba does not appear to 
have been noticed, and of which the function is quite unknown. 
These are two invaginations of the ectoderm which start from the 
ventral surface of the first abdominal segment and extend like the 
fingers of a glove to the extremity of the fourth segment or a little 
further. The author regards them as homologous with the stridu- 
lant organs of the male Cicadas. In the males of 7. Douglasiand 7. 
hippocastant infested by Aphelopus or Atelenevra the ventral invagi- 
nations are much reduced, reaching only, in general, to the second 
abdominal segment, and often forming only two little pockets on the 
first segment. 
Aphelopus melaleucus appears to be pretty common; it has been 
met with at Wimereux and in the wood at Meudon upon 7. hippo- 
castani and 7’. ulmi, which often live together upon the elm, with 
T. opaca, J. Edw. In these localities the sac which contains the 
larva instead of being yellow as in the Luxembourg garden, is usually 
of a blackish colour. This colour is evidently protective of the more 
numerous individuals living upon 7. w/mi, the abdomen of which is 
black, and is probably due to heredity in the others. Perhaps, 
moreover, Aphelopus presents varieties in the different species of 
Typhlocyba which it infests: Walker has described fifteen forms of 
this Hymenopteron, and the individual figured by him differs in 
certain characters from those examined by the author, who says 
that) he has been unable to find the least trace of the cells of the 
fore wings, and that the palpus possesses only five joints instead of 
six.—Comptes Rendus, Noy. 4, 1889, p. 708. 
