64 Mr. Westwood on Siagonium quadricorne, Sec. 



would divide the family Omatkice into two sections — the first com- 

 posed of the genera Omalium^ Froteinus^ Jfithopagus, Eloniurn^'^ 

 &c. and the second comprising Oxytelus^ BlediuSj Evcesihetus^ &c, 

 and then the connexion between the genera appears strikingly 

 natural : Eloniiim^ combining in itself the external appearance of 

 an Oxytelus^ and the maxillary palpi oiOmalium (to which genus it 

 bears great affini(y,and of which, the type El. striatulum was a spe- 

 cies, both with Gravenhorst and Gyllenhall), joining the two sec- 

 tions at one point, where the insects of both sections are of an elon- 

 gate form, and the interesting genus Evcesthetus (in external ap- 

 pearance resembling the depressed Ojjiatia^ and more particularly 

 Om, refusum (which will form a new subg'enus) and which until 

 separated by Gravenhorst, was placed in the genus Oocyielus 

 and which De Jean has also placed between Oxyttlus and Oma~ 

 Hum ;) serving to connect the two sections at the other point, 



* Staphylinus striatiilus, Fab. (Om. rugosum, Gr. Gyll.) has been formed 

 into the genus Elonium by Dr. Leach— but I believe no characters have yet 

 been published of it. 



Plate II Fig. 6 represents the Maxilla of this Insect. 



Fig. 5 ditto of the genus Omalium. 



(the type of which I consider to be Omal. rivulare) 



Fig. 7 ditto of Oxytelus carinatus, 



(Staph, rugosus Marsh.) which I consider as the 

 type of that genus. 



Fig. 8 ditto of Siagonium quadricorne. 



Fig. 9 ditto of Zirophorus fronticornis. 



And it is not a little singular that tliese two last Insects, which, from their ap- 

 parent aflBnity with Oxytelus, we miglit infer would possess maxillary palpi 

 similar to those of that genus, present these organs nearly agreeing in form 

 with those which Omalium possesses. Indeed from my own observations on 

 the subject, I have little hesitation in saying, that the maxillary palpi alone do 

 not present characters sufficiently precise to enable us to found our divisions 

 upon them, and I am confirmed in my opinion by Mr. MacLeay's remarks, 

 both in his Horoe Ent. Part. 1. and also in his Annulosa Javanica, and more 

 particularly in his observations in the last mentioned work on Latreille's 

 Section of Carabidae " Subulipalpes" (Bembidium) which was established on 

 the same organ : and Mr. Kirby likewise in his Century of New Insects, (Lin. 

 Trans. Vol. 12), speaking of the comparative length of the maxillary and labial 

 palpi upon which the genus Megacephala is built, gives it as his opinion that 

 it merely indicated the section of a genus, rather than a Genus. 



