1864.] • 239 



{Sill. Jour)i., Vol. 35, p. 66,) or in other words in lega being converted 

 into head-organs. And in Crustacea this character really appears to 

 be of high systematic value. It by no means follows, however, as every 

 Naturalist is well aware, that because a character is of high systematic 

 value in one group, it will be of equally high value, or of any value at 

 all, in another group. The neuration of the wings is of high systema- 

 tic value in most Orders of insects, but in Coleoptera it is utterly worth- 

 less, or at all events, according to LeConte, " no results of importance 

 for classification have yet been obtained by the study of the venation 

 of these organs." (^Intr. Col. p. xviii.) Again, in Odonata the neura- 

 tion is very constant in the same species and differs very much in dif- 

 ferent genera ; whereas in the closely allied Perlina the neuration is 

 very inconstant in the same species, insomuch that the number of sub- 

 terminal cross-veins varies from 2 to 12 in different specimens of the 

 same species (Acroneuria ahnormis Newm.), and in the right and left 

 wing of the same specimen there is sometimes a difference of 4 subter- 

 minal cross-veins, {Acr. ahnormis Newm. and Perla varians Walsh) ; 

 while on the other hand the neuration of this family differs compara- 

 tively but little in the different genera. Hence it results that in Odo- 

 nata the neuration is of the highest systematic value, and in Perlina 

 of much lower value. 



If we apply the principle of Cephalization in its original signification 

 to Insects, we shall find that there are certain families and irenera, e. sr. 

 in Orthoptera Mantidae, in Neuroptera Mandspa, in Heteroptera 3Ii/o- 

 docha, Phymata., Macrocephalus., Syrtis, Reduviidse and Ne.pidse^ and in 

 Diptera Hemerodromia., which have what are commonly known as rapto- 

 rial front legs ; in other words the front legs are used, not as legs but as 

 arms to catch their prey with. In other species, e. g. the dipterous 

 Galohata antennsepes Say, which takes its name from that peculiarity, 

 and in many Nemocerous Diptera, the front legs are not used at all for 

 locomotive purposes, but are elevated in the air and vibrated after the 

 fashion of antennae. Here therefore it is strictly true that " the ante- 

 rior members of the thorax are transferred to the cephalic series;" and 

 if, as Prof. Dana maintains, the cephalization of the anterior pair of 

 limbs in Man, or in other words the conversion of his front limbs into 

 arms, "places Man apart from the whole series of Mammals" {Sill. 

 Journ.^ Vol. 35, p. 68), then by parity of reasoning, if the principle of 



