66 THE ENTOMOLOGIST. 



of the species. The same author, in a paper recently read 

 before the Academie 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 23id 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 

 Phylloxeras which are sent him, whether of the root or leaf- 

 gall type ; and that this vine is still alive, in spite of the 

 Phylloxerae 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 Phylloxerae 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 

 interesting communication by M. Meguin, published in the 

 Paris 'Journal d'Anatomie et de Physiologic,' intituled 

 "Memoire Anatomique et Zoologique sur un nouveau Acarien 

 de laFamille 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-larvae 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 Phylloxerae. 



