■92 FIFTH ANNUAL REPORT 



attributes of the Coccidce, and precisely similarly knobbed hairs are 

 found at the antennal extremities of some species — e. g. Le.caniura 

 aceris (Schrank), auctore Signoret. 



Mons. V. Signoret, of Paris, has lately been engaged on an elabo- 

 rate monographic revisionf of the insects of this family. This distin- 

 guished author has, perhaps, devoted more time to the Coccidce than 

 any one living ; and in his admirably illustrated essay, with copies of 

 which he has favored me, the Coccidce are divided into four distinct 

 subfamilies, distinguished by the more obvious characters, as follows: 



0.. — DiASPiDES : — Species covered with a scale composed of successive moUings, and of 

 a secretion forming a shield or sack more or less independent of the body of the 

 animal. 



Nine genera are included in this subfamily, but tlie scales may all be re- 

 duced to two principal types, viz : Those witli rounded shields, like an oyster- 

 slielL with tlie larval scale in the center ; and those with more lengthened 

 shields, in the form of a large comma, or of a muscle-shell, and having the 

 larval scale at one end. 



Among, the latter is the genus Mi/tilaspis, to which our apple-tree species, 

 under consideration, belongs, and whicli is chax'acterized by the male and 

 female shields having much the same form. 



"2. — Brachyscelides : — Species living in gall-like or tube-like excrescences. These insects 

 are, so far as Ivnown, confined to Australia. 



-§. — Lecaxides : — Species either naked or inclosed, or siinplg covered with loaxy, cnlcaremis 

 or filamentous secretions ; and in which the female, after fecundation, generally 

 acquires an entirely different form to that which she previously possessed, and 

 becomes fixed. Before pregnancy, th''y have the power to move, if neeessa7-y. 



A number of genera are included in this subfamily, some of which, ap- 

 proaching in some characters to the Diaspides, have been separated by Tar- 

 gioni, under the name of Lecanio-diaspides. 



A. — CocciDES ; — Species retaining to the end the body-form, with all its joints distinct. 

 They never become necessarily fixed, arid are either naked or more or less covered 

 with waxy or spumous matter, arranged generally in filaments. 



Specific Name. — In considering the specific name of this insect, 

 we meet with the same difficulty which constantly presents itself to 

 the conscientious student of animal life, especially in its lower forms ; 

 and there can be no stronger argument in favor of the mutability of 

 species than this difficulty experienced in properly defining them. 

 All nature is a whole, and our classificatory divisions, though very 

 essential to enable us to study and understand her, have hardly a 

 more real existence than the divisions by which we measure time. 

 With partial knowledge, only, of her facts, it is easy to separate and 

 draw distinctions in the cabinet; but deeper knowledge of these facts 

 often begets doubt and difficulty, as to these distinctions, and shows 

 the unnaturalness of strict and fast definitions. 



With our bark-lice, as already stated, it has been customary to 

 consider the forms found on different plants as distinct species. No 



^ Essai sur Ics Cochenillcs, in Annates dcla Soc. Ent. de France, commencing in 1868. 



