Miscellaneous. 229 
circumstance happen to destroy the winter-egg, there is always a 
subterranean provision of reproduction ready to replace the sexual 
generation which has not prospered. 
Moreover, in the case before us, the winter-egg, that is to say the 
fecundated egg of the Tetraneura, besides being well sunk into the 
fissures of the bark, is further protected by the dried skin of the 
mother, for she does not expel it, but keeps it encysted within her, 
as do the Aphides of the galls of the Lentiscus observed by Prof. 
Derbes. Thus protected the egg braves the attacks of mites, Heme- 
robil, Thrips, and other small enemies. 
In indicating the two species of grasses upon which I have found 
the subterranean forms of Tetranewra, I do not wish to imply that 
they do not attack others; on the contrary, I know very well that 
Passerini, for example, cites eleven species of grasses upon which he 
has found his Pemphiqus Boyeri, which now becomes synonymous 
with Tetrancura ulmi; and as the latter is everywhere very com- 
mon, it is very probable that in countries where maize or the dog’s- 
tooth grass are wanting, it contrives to find other grasses to its 
taste. I believe this species is polyphagous. 
But if it is polyphagous in its subterranean phase, it appears to 
be very faithful to the elm and even to Ulmus campestris in forming 
its gall. In fact I have, side by side with Ulmus campestris, two 
or three plants of Ulmus effusa, a tree very nearly allied to the 
former species, which the botanists can hardly distinguish except 
by the form of the flowers. Now at this present moment the elms 
have neither leaves nor flowers, and I put the same strip of paper 
upon Ulmus effusa as upon Ulmus campestris; nevertheless the 
insect makes no mistake, and I never find a Tetraneura upon the 
Ulmus effusa. On the other hand there is upon the latter tree a 
peculiar gall of a species of Aphis very nearly allied to Vetraneura, 
namely Schizonewra compressa, Koch. This arrives in numbers upon 
the species of elm that it prefers. I do not yet know whence it 
comes. Here, therefore, we have Aphides which, cleverer than the 
botanists, can recognize in the winter trees which the naturalist can 
only distinguish in summer by their flowers and fruits. Of course 
I make no attempt to explain such phenomena as these; I do not set 
up hypotheses, and confine myself to indicating exact facts, which I 
observe with the greatest possible attention. The problem of the 
biological evolution of the Aphides of the elm was enunciated more 
than a century ago; it is now solved.—Comptes Ltendus, December 
31, 1883, p. 1572. 
Note on two New California Spiders and their Nests. 
The Rey. Dr. McCook presented a small collection of spiders re- 
ceived from Mr. W. G. Wright, San Bernardino, Cal., mailed 
November 18. One of these came within a nest, and is a Saltigrade 
spider, probably an <Attus. The nest is a rare one, and was so 
happily placed, by the builder, on a branch of sagebrush (Ephedra 
antisyphilitica) that it was preserved intact. It is the only one 
