284 COLEOPTERA OF NORTH AMERICA. 



differentiation of tribes seem to me to be of but small, or still 

 worse, illusory importance ; and among these, the extension out- 

 wards of the middle coxse, so that they attain or not the epis- 

 terna is one of the most indefinite, and I have, therefore, rejected 

 it as far as possible in the following scheme. 



I have, in common with previous investigators, failed thus 

 far to find any distinct difference capable of expression in words 

 between this family and Chrysomelida?. One familiar with the 

 subject will rarely if ever mistake one for the other. But so far 

 the essential difference between the Tetramera, of which the larvae 

 feed upon wood, and those feeding upon cellular vegetable tissues 

 has eluded observation. I can merely at present observe that a 

 slight approximation to it seems to be made in the fact, that in 

 the Cerambycidae there is a tendency in the epimera of the meta- 

 thorax to extend to the sides of the ventral segments, while in 

 the Chrysomelidaa the 1st ventral is prolonged forwards at the 

 sides to meet the metathorax ; thus showing probably a lower, 

 though necessarily more recent, type, which could have existed 

 only since the development of the higher broad-leaved plants. 



And in continuation of this same subject, I would refer the 

 difficulties of classification of the Longicorns to the fact, that 

 being exclusively feeders upon woody tissue, and passing a very 

 long period in the larval state, in the interior of trunks or 

 branches of trees, protected against inundations by the buoy- 

 ancy of their juvenile homes, they have been peculiarly qualified, 

 not only for an early introduction, but prolonged existence ; and 

 that we, therefore, have here a more perfect record than is likely 

 to occur in any other land animals. Among marine objects fre- 

 quent examples occur of the representation in the existing fauna 

 of forms more fully represented in previous geologic periods ; 

 but this is the first instance in which we have had occasion to 

 note the probability of its occurrence in the Coleoptera. I have 

 already alluded to this subject,* specially in connection with the 

 Spondylidse, and have been very glad to find that the idea has 

 been approved of by my friend H. W. Batesf , the distinguished 

 explorer of the Amazon, in words so expressive that I cannot 

 forbear quoting them. 



* An attempt to Classify, &c., Journ. Acad. Nat. Sci. 2<3, II. 99, (1851). 



f Contributions to an Insect Fauna of the Amazon Valley, Coleoptera, 

 Longicorues, Part I. Lamiaires, p. 5-6 (from Annals and Mag. Nat. Hist. 

 1861). 



