BIBLIOGBAPHICAL AND NOMENCLATORIAL NOTES, ETC. 255 



The genera Aplds, Chermes, and Psylla also, in most recent 

 works, are evidently incorrectly determined. Ajyhis was founded 

 by Linne in 1758, and continued undivided till 1801, when 

 Lamarck fixed ulmi, Linn., Geoffr., Fab., as the type. This, 

 however, is not Lachnus ulmi (Linne), as the addition of " Geof- 

 frey, Ins. i. p. 494, 1. 10, f. 3," shows, but is the so-called " Tetra- 

 neura ulmi, JJe Geer,"* and therefore, not being a Linnean species, 

 cannot affect the type-fixation. The next year Latreille selected 

 sambiici, Linne, as the type, this being available. 



Chermes has by some been included in the Coccidae, by others 

 in the Aphidas, and by others in the Psyllidse ; the latter is the 

 correct position, and the family should be known as Chermidse.f 



Founded in 1758, the genus was turned aside by Geoffroy in 

 1762,]: to include part of Coccus (because " Kermes " was the 

 Oriental name for certain Coccidffi !) and Psylla formed instead. 

 The latter is therefore a pure synonym of Chermes, Linn., the 

 type heingjicus, Linn., Lam., 1801. 



Coccus was divided by Geoffroy in 1762 (see footnote), and 

 although, owing to the local faunistic nature of the work, 

 the type cannot be definitely fixed, he certainly must be con- 

 sidered to restrict it to those forms which are characterized as 

 *' Foemina insecti formam servans." The species he removes to 

 Chermes, Geoffr., nee Linn., are characterized " Foemina folliculi 

 formam induens'' ; it is from this group that Mrs. Fernald has 

 unfortunately chosen the type of Coccus (Canad. Entom. xxxiv. 

 232). § 



As the type of Coccus, Lamarck (1801) selected " Coccus 

 mexicanus. Lam. — Coccus cacti coccinelliferi Lin., Coccus cacti, 

 Fabr., Eut. (= Dactylopius coccus, Costa, which it must super- 

 sede, the cochenille insect becoming Dactylopius mexicanus 



■•' The correct name is Tetraneura gallarum-ulmi (De Geer). 



f I do not think it is necessary to forni this name as Chermetidae. Most 

 entomologists appear to beheve that the stem of all words modelled on the 

 third declension of Latin nouns must end in t or d; hence Tingitidce, 

 instead of Ting idee ; Gei-rididcc, instesidi of Gerridce ; Cher 7netidce, inste&A 

 of Chermidce ; Aphididce, instead of Aphidce, &c. 



\ A great deal of unnecessary trouble has been caused by the dispute as 

 to the validity of Geoffroy's names. But even if Gcotfroy, 1762, be denied, 

 Miiller, 17G4 (except Tetigonia), or Geoffroy in Fourcroy, 1785, must be 

 accepted. I do not know one single Hemipterous genus that is at all vitally 

 affected; for Tetigonia one simply has to write 1785 instead of 17G2, and, for 

 the rest, " Miiller, 17G4," instead of "Geoffroy, 17(32." 



§ As regards the definite fixation of the type of Coccun, GeofTroy is ex- 

 cluded, first because he specifies no type, and secondly because his woi'k is 

 not a "Histoire abregee des Inscctcs," but a " Histoire abregee des Insectes 

 qui se trouvent aux environs de Paris ; " therefore, apart from types spe- 

 cially noted, or species of genera thereon erected, has no more value for our 

 present purposes than a mere list of captures, the inclusion of certain species 

 being due simply to the faunistic nature of the work. This applies also to 

 Schranck, Scopoli, and other authors, often cited in the type-fixation of 

 genera. "Historical" type-fixation can come into force from 1794 (as 

 regards Homiptera) when Fabricius instituted the type-system. 



