INTRODUCTION'. XXIX 



to the femora or tliiglis close to the coxa, and forms an integral portion of 

 the legs ; following the femora come i\\Qtibiie, at the extremity of which 

 are usually found two movable spines or spurs, which vary very con- 

 siderably in length, and one of which or even both may be absent ; 

 attached to the tibipe come the tarsi, which are never composed of more 

 than five joints or less than two ;* hence we have the old divisions of 

 Pentauiera, Tetramera, Trimera, &c. ; often the number of joints is 

 different in the different feet as in the large class Heteromera, the species 

 belonging to which have the anterior and intermediate pairs made up of 

 five joints, and the posterior of four only : in the Staphylinidse the 

 variation of the number of tarsal joints affords a very valuable character 

 for the classification of genera; some genera, e.g. R]tizopha<ius, are 

 heteromerous in one sex only ; the tarsal joints vary very greatly in form, 

 and are very differently dilated in the sexes of the same species ; this 

 dilatation and the clothing of the uiuler surface of the joints (whether 

 jmbescent, squamose, ite.) aff'ord a most valuable character for the classi- 

 fication of the Carabidie ; the last tarsal joint bears the claws, and is 

 called the omjchium ; the penultimate joint or last but one is often 

 bilobed, especially in the plant and tree-frequenting beetles ; the claws 

 are of very different shapes, and may be simj^le, toothed, serrated, 

 or pectinate, or furnished with membranous appendages at their 

 base. 



The different formations of the legs as a whole will l^e fTU'thcr alluded 

 to during the course of the work ; the most noticeable deviations from 

 the ordinary form are the natatorial or swimming legs of the Dytiscida", 

 t\iQ fogsorial or digging legs of the Scaritidse, Geotrupidee, &c., and the 

 ^altatorial or jumping legs of the Halticidse, in which latter the femora 

 are very strongly thickened. 



The Abdomkn. 



All that portion of the body situated behind the metasternuiu is called 

 the abdomen or hind body, and consists of a series of rings divided into 

 two portions, the dorsal segments (more or less covered by the elytra) 

 and the ventral segments, which are united to the former on the dorsal 

 surface, usually by membrane ; these segments are properly nine in 

 number, but, as a rule, oid}^ five or six can be distinguished : of these 

 segments the last dorsal segment is called the j;//r/«V?ewwi, and the last but 

 one the propi/i/idium ; in the Nitidididie and liistcritlaj two or three of 

 the apical dorsal segments are visiljle ; in the large family of the Sta- 

 phylinid;e the upi)er surface of tlie abdomen is almost entirely 

 uncovered. 



As the terms apex and base are very often used in descriptions every 

 student should thoroughly understand how they are employed in the case 

 of different parts of the body, or else much confusion will arise : in the 



* One or two exotic gunciti appeal- to be moiiouierou!:, but it is somewhat doubtful 

 if they retilly are so ; very larely the claws and even the anterior tarsi are wantiiiy. 



