COLEOPTERA. 



41 



Ex. Typic. 



f3. Philhydrida. Hijdrophilus. 



2. Aberrant group, consisting 

 of insects having their 

 antenna; clavate, or at 

 least gradually thickened . 

 towards the apex, while 

 the external lobe of the 

 maxillsE is not palpiform. 

 [RYPOPHAGA Stcph.] 



Necrophaga. Silpha. 



y_5. Brachelytra. Stnphi/Uniis. < 



Families. 

 Heterocerida; ? 

 Parnidju. 

 Helophoridas. 

 Ilydrophilida". 

 S|)lia'ridiida2? 

 ■Scapiiidildjc. 

 Silpliida;. 

 Nitidulida?. 

 Engida2. 

 DermestidcB. 

 StaphylinidfB. 

 Steiiida;. 

 OmalidfB. 

 Pselaphida;. 

 Tachyporida;. 



The circularity of this tribe is supposed to be effected by the ap- 

 proximation of Lesteva amongst the Brachelytra to the Carabidte. It 

 must be borne in mind that the analogies existing between these five 

 types of Coleopterous larva? and the five groups into which Mr. 

 MacLeay divides his class Ametabola, constitute Mr. MacLeay's chief 

 argument in support of their correctness. * The above is the sub- 

 stance of Mr. MacLeay's hitherto published views upon this subject, 

 whence the impossibility will be seen of following them out through 

 the entire order, and which is indeed the more increased from our 

 great ignorance of the larvae of many important groups. We 

 have seen also that Mr. MacLeay himself admits the existence of a 

 variation in the tarsal structure concurrent with the variation in the 

 form of the larvae, a circumstance dependent, as it seems to me, upon 

 the principle that modifications of the preparatory states of an insect 

 ought merely to be regarded as indications of corresponding pe- 

 culiarities in the final state, the former modifications being subordinate 

 to those observed in the imago, having in fact been undergone with a 

 direct view to the perfection of the insect. We might indeed carry 

 the subject still further. Thus, whilst the intimate connexion ex- 

 isting throughout the whole of the Tetramerous Beetles cannot be 

 denied, yet Cerambyx has a subvermiform and Chrysomela an 



* It is to be observed, that IMr. INIacLeay's views respecting the Ametabola liave 

 been adopted by no subsequent author, and that Messrs. Kirby and Spence (who 

 regard INIr. MacLeay's proposed distribution as requiring much more consider- 

 ation and investigation than have hitherto been given to it — fntrod. iii. 161.) 

 have pointed out numerous other and equally striking analogies' existing 

 between the Coleopterous larvfe and the Crustaceous and Arachnidous classes 

 {Iiitrod. iii. 166.) 



