COLEOPTEUA. ENGID^. 143 



mosoma, &c., induces me, in accordance with the views which I have 

 more fully detailed in the sixteenth volume of the Linncean Trans- 

 actions, to keep the two groups distinct. 



The fourth family Engid^e MacLeay is an extensive group of 

 insects, of very difficult location in a natural system, differing from the 

 Nitidulidai in the more elongate form of the body and simjjle tarsi, 

 and from the Dermestidas in the more developed structui-e of the 

 mandibles, and the generally more glabrous body. So diversified, 

 however, is the structure of the various minor groups introduced by 

 MacLeay and Stephens into the family, that it is next to impossible 

 to lay down any general character. Latreille, as before observed, 

 from giving too great a weight to the tarsal system, distributed these 

 insects amongst his Pentamerous, Heteromerous, and Tetramerous 

 sections ; the greater portion, however, constituted his tribe of Xylo- 

 phaga introduced between the Rhyncophora and Longicornes ; Sco- 

 lytus, Apate, &c., being considered as the links uniting the group with 

 the former, and Trogosita and Cucujus with the latter. It is true, 

 indeed, that in many of these insects there are but four distinct tarsal 

 joints ; but at the same time it is equally evident that the great di- 

 visions typified by Curculio and Cerambyx have so strikins; an uni- 

 formity in the structure of their tarsi and the apod character of the 

 larvae, that the introduction of such heterogeneous groups as La- 

 treille's Xylophaga between them cannot be considered otherwise 

 than as most unnatural. We know, however, too little of these groups, 

 most of the species of which are of minute size, and have been much 

 neglected, to speak with precision upon their various relations. In 

 the Regne Animal we find these insects forming the following tribes : — 

 Engidites amongst the Pentamera ; the typical genera Paussus, Bos- 

 trichus, Monotoma, Mycetophagus, and Trogosita, amongst the Xylo- 

 phaga, and the tribe of Platysoma (Cucujus). Mr. MacLeay also 

 considers Triplax and Languria to enter into the family Engidaj, which 

 latter genus would also necessitate the introduction of the Erotylidnc, 

 the real pentamerous structure of the tarsi of which is clearly proved 

 by an examination of such genera as Ips, Engis, Triplax, and Ero- 



