OP III;'. UNITED 6 



heretofore been unnoticed. In the natatory genera, the posterior coxa ia larger than in the 

 terrestrial genera, and extend? completely to the side of the abdomen, thus cutting off all 

 articulation between the epimera of the metasternum and the ventral Burface of the ab 

 men : now the effect of this is to give an increased attachment for the muscles moving the 

 long posterior legs, so that they may have the requisite power for Bwimming. The u kv 

 ologist might say that this was a simple effect of the natatory h'L r s: unfortunately, how- 

 ever, there happens to he a genus found in California, ■which, witli this form of coxa, (re- 

 duced only a little in size,) has perfectly ambulatorial feet, so that in this case it is evident 

 that the enlarged coxa, a zoological character, having only indirect relation to the man- 

 ner of life, has considerably more value in establishing the relations of the two organisms 

 than the mechanical character of the form of the I 



Leaving the full development of these considerations, which belong more properly to 

 transcendental zoology, I will proceed to sketch out the general fact- by which I have 

 been guided in my arrangement of Geodephagous Coleoptera. 



In the first instance we have two very distinct forms recognised by most entomologi 

 as types of distinct families. These are the Cicindelidse and ordinary Carabidos. The 

 definition of the first family has been gradually modified according to our more accurate 

 knowledge, until finally it rests merely on the character proposed by Erichson, " ligula cor- 

 nea, inlle.xa, paraglossis nullis." On close comparison I find that the antennas arc diffe- 

 rently placed in the two families, being on the front above the base of the mandibles, ia 

 Cicindetide, and behind the base of mandibles in the genuine Carabide. Another verj 

 remarkable dillerence of a sexual character is, that the abdomen of the male i- composed 

 of seven ventral segments, while the female has but six, as in ordinary Carabii 



Having now isolated the Cicindelidse, we may pass on to the consideration of the se- 

 cond family, as the very complete essaj of M. Lacordaire* leaves nothing to lie added. 

 A classification of the numerous species found within our country requires a Bynopsis, and 

 must be deferred for a more appropriate occasion. 



In glancing over a large series of Carabica, it i< evident at first Bight that there are at 

 least bix distinct groups, viz.. Lebia, Pterostichus, Harpalus, Chiasmus, Scariti -. and < !ara- 

 bus: although there may be gradations from one to the other, yet the eye singles tl 

 out as being the types of different divisions. In comparing these with each other we find 

 a general correspondence of those characters which separate them from Cicindelidaa, but 

 in the more intimate structures we fuel a great difference. The form ol the anterior ti- 

 bia' has been used by Erichson, and of the Bternum by Halidaj : these appear bo diff< n nl 

 in form in genera which are closely allied, that it isobvious that their importance 111 i 

 blishing the primary divisions has been unduly estimated. On comparing together the be- 

 fore-mentioned six types, I found that a character i lists m the sid< -pit 1 1 - of the mi 

 sternum, whuh would give us a primary division apparently lie- from objection, In the 

 ordinary Lebia, Pterostichus, vVc this Bide-piece is quadrilateral, with a tine scarcely pert 

 ceptible suture along its posterior margin. InScarites andCarabus this fine posterior suture, 



* Revision de la Famille I Mem. £ ' 



