66 THE ENTOMOLOGIST. 
of the species. The same author, in a paper recently read 
before the Académie des Sciences (December 14th), enume- 
rates sixteen well-defined species of Phylloxera indigenous 
to North America; whereof only one is found on the vines, 
and one (P. Rileyi) on the oaks; the others being chiefly met © 
with on different species of Carya. It is, moreover, worthy 
of remark that M. Signoret, on the 23rd of September, 
informed the Entomological Society of France that he still 
possesses a potted vine, whereon his first experiments were 
made in 1869; that every year he places on this vine the 
Phylloxere which are sent him, whether of the root or leaf- 
gall type; and that this vine is séz// alive, in spite of the 
Phylloxerz upon its roots; retaining its verdure, though not 
in very thriving condition, from having been five years in the 
same earth and the same pot. A species of Acarus (the 
Tyroglyphus Phylloxere of Riley), which preys upon the 
root-inhabiting type, has been discovered by Mr. Riley in 
America, whereof colonies are being introduced into France ; 
but Mr. Riley considers that any expectations founded 
thereon are doomed to disappointment. The T. echinopus, 
described by Dr. Fumoze and Prof. Ch. Robin in 1868, has 
also been found on the French vines. Another species of 
Tyroglyphus, met with abundantly on Fungi, more especially 
on the Agaricus campestris, has been the subject of an 
mteresting communication by M. Méguin, published in the 
Paris ‘Journal d’Anatomie et de Physiologie,’ intituled 
“ Mémoire Anatomique et Zoologique sur un nouveau Acarien 
de la Famille des Sarcoptides, le Tyroglyphus rostro-serratus, 
et sur son Hypopus,” showing that the latter is but an 
adventitious nymph-form of the former, which the octopod- 
nymphs assume by moulting, when the Fungi become 
desiccated, resuming their previous nymph-condition by 
another moult on the moisture being renewed. This 
incidental heteromorphosis not extending to other stages, 
the hexapod-larve and adults are doomed to perish under 
such circumstances, while the occult-nymphs, in their 
Hypopus coat-of-mail, attach themselves to any insects that 
come in their way, for conveyance to another suitable abode, 
whereby the continuance of the race is provided for. A 
similar transmutation has been observed by MM. Riley and 
Planchon in the Tyroglyphus Phylloxere. 
