AMERICAN COLEOPTERA. 83 



edjre of the niautlible, runiiiiiii- backwards in a nearly strai<iht line 

 under the insertion of the antennae and the eyes to the hind angles 

 of the head, slightly curved upward posteriorly. This ridge is honio- 

 logically c(|uivaleiit to the margin of the thorax or more accurately 

 the line of division between the upper and lower components of each 

 segment of the body, and indicates that the mentum and maxillne and 

 their apjiendages are inferior while the antennae, mandibles and labrum 

 are superior. In some short-beaked Rhynchophora there is a very 

 distinct suture, indicating the sauic structure, which starts from the 

 lower border of the eyes, dips down under the head and beak so as 

 to nearly surround the scrobe and passes forward to the side of 

 the buccal opening. Similar faint sutures of like import have beea 

 noticed in various other families* in immature specimens, and a more 

 extended study of the.se sutures about the head will enable its parts to 

 be more correctly homologized with the other segments of the body. 



The marginal ridge of the head is found in this tribe in the three 

 genera constituting the group IJolitobii. It reappears as might be 

 inferred in the closely allied group Quedii of the adjacent tribe 

 Staphylinini, and finally entirely disappears in the genera allied to 

 St(ij>/u//iiin^. I have seen the ridge in some Alaeocharini also, but 

 an investigation of the characters of other tribes not being pertinent 

 to the present es.say will be left for a future occasion. 



From the importance of several characters noticed in the preceding 

 pages it seems necessary to divide the genera into groups or sub-tribes. 

 This h.is already been ])artially dune by Fauvel in the '' Fauna (lallo- 

 llhenane," in which three groups are estal)lished, one of which I pro- 

 pose to again sub-divide, based on other characters than those in the 

 following t.ible. 



The following is the method of sub-division : 

 Po.sterior cnxne altaiiiing the side pieces of the iiietathorax; usually expanded 



into a [ilate the free edge of which conceals the first and a portion of the 



second segment. 



Antennae ten jointed, tarsi four-jointed Hypocypti. 



Antennre eleven-jointed, tarsi live jointed. 



Head not niaigined Tachypori. 



Head margined at the sides Bolitobii. 



Posterior coxje triangular. Antenn.ie ten- tarsi five-jointiMl. 



Head not margined beneath Habroceri. 



f Since the above was written Dr. Leconte has noticed the existence of the 

 ridge on the underside of the head in Cicindelidte, and «n examination made 

 at once showed that while it exists in all our genera of tiiat family it is not 

 present in any of our CarabidjB. Should tliis hold good vviili genera not in our 

 fauna it gives an additional character for separating the two families. 



