456 
Miscellaneous. 
marked distinct genus, forming the transition between the Coccidae 
and the Phylloxeriaus, with which I have already frequently occupied 
the Academy. This is what I have been able to observe. 
In the months of August and September, I saw, running about 
upon the trunk of a young elm (Ulmus campestris), some small red 
plant-lice 045 millim. in length, of an elongate-oval form, with six- 
jointed antennae. These insects attach themselves in the crovices of 
the bark, and then gradually lose their Aphis-like form, to acquire 
that of a small flattened reniform gall or vesicle, as is the case in 
many Coccidae. At this period the present form approaches the 
genera NidulaHa , Targioni, and Gossyparia, Sign., inasmuch as it 
exudes a cottony mass underneath it, in which it deposits ovoid 
bodies which are not true ova, but analogous to what I have deno¬ 
minated pupa in the Phylloxerians. In fact, in March these little 
ovoid bodies, which are of various dimensions, acquire traces of 
segmentation, which become more and more visible; and in April we 
see small red insects, which are the males, issue from the cottony 
mass. 
Their antennae, moniliform and of nine joints, are like those of 
the Coccidae, especially those of Gossyparia ulmi , Sign. (“ le Pro- 
gallinsecte de l’Orme” of Reaumur), which, however, have one joint 
more (ten) ; but in other respects the form is by no means that of 
the male Coccidae, but that of the Phylloxerians. The head, thorax, 
and abdomen are united as in the sexual individuals of Phyl¬ 
loxera (or, I might add, of all the Pemphigians), and not separated 
as in the Coccidae. Lastly, the little animal is completely apterous, 
destitute of a rostrum, and provided with a projecting penis ; its 
length is 0*40 millim. 
Here I cannot refrain from indicating a very curious fact in the 
males of the Coccidae of tho elm. Four different genera live upon 
this tree. Two of them, Lecanium and Mytilaspis , have the male 
form winged ; a Gossyparia presents males with rudiments of wings ; 
and, lastly, the one I am now describing, Ritsemia , has a perfectly 
apterous male. 
A few days after the appearance of the males, the little ovoid 
pupae which have remained in the cottony mass are developed in 
their turn, and furnish the female, which is a little larger than the 
male (045 millim.), and very similar to the form that appears in the 
month of August ; only it has eight joints in the antennae instead of 
six, and is therefore not the same biological phase. 
Copulation takes place at the time ; and I do not know what occurs 
between May and August. Notwithstanding this gap, I think it 
desirable to make known what I have observed, in order to call 
attention to the study of the plant-lice of the elm in general, which 
is still so incomplete. I know eight upon this tree, the four 
Coccidae cited above and four Aphididae — Tetraneura ulmi , T. alba , 
Schizoneura ulmi, and S. lanuginosa. These insects occur in millions 
upon every elm ; the problem of their biology has been set ever since 
the time of Reaumur, and it is still to be solved. We are acquainted 
