46 MODERN CLASSIFICATION OF INSECTS. 



in both sexes. The Bimani (Dimani j^.), or those with the two an- 

 terior tarsi of the males dilated, are most numerous amongst the 

 Geodephaga, and exist also in Hydaticus and Acilius, whilst the 

 Quadrimani are more numerous in the Hydradephaga, and also in the 

 subfamily Harpalides. The number of dilated joints varies from one 

 to four, the basal joint exhibiting the greatest degree of dilatation. 

 There is also considerable variation in the form of the dilated joints, 

 and which (as in the Patellimani) has been employed to characterise 

 divisions. An equally important character exists in the lining of the 

 sole of these dilated joints, which Mr. Kirby describes (without being 

 apparently acquainted with the observations of Messrs. L. Dufour 

 and Audouin, subsequently alluded to), and divides the Adephaga 

 into three sections thereupon, namely : — 



1. Sarrothropoda, or those with the dilated joints clothed beneath 

 with a dense brush of stiff hairs: Cicindelidae, Carabides, Chlaenius 

 and its allies. (See also Aud. and UruUe, Hist. Nat. Ins. Col. 

 vol. i. p. 395. and 44-4'.) Others have only a few hairs at the sides 

 of the joints of the tarsi. 



2. Cystopoda, or those with the foot-cushions formed of little mem- 

 braneous vesicles or cysts variously arranged : Brachinus, Agonum, 

 and various Harpalides. In Helluo and Anthia the dilated joints 

 are furnished with lateral brushes, and in the middle with vesicles. 



3. Pyxidiopoda, or those with the foot-cushions formed of pedun- 

 culated cups or suckers : Dyticidse. 



In the figures accomi^anying the various groups of Adephaga, I 

 have illustrated the variations in these foot-cushions, which will 

 thence be seen to be more numerous than stated by Mr. Kirby. 



These insects are extremely active, and eminently predaceous, 

 devouring other insects with great avidity, and occasionally not even 

 sparing their own species. This subtribe is divisible into two* stirpes, 

 according to the element in which the insects reside — 



The 1st, Geodephaga, being terrestrial! . , . , , . 



^ ^ *= '^ni their habits. 



lal 1 , 



id' 



The 2d, Hydradephaga, being aquatic 

 The former very far exceeds the latter in the number of its species. 



* Mr. Kirby {Fami. Bor. Am. p, 6.)has proposed another stirps, Hygradephaga, 

 for those Carabideous insects delighting in liumid places (the Acutipalpi,Subulipalpi, 

 and Elaphridce), constituting an intermediate or transition group between the Geode- 

 phaga and Hydradephaga. I cannot, however, find any decisive characters for such 

 a separation of insects so closely allied together as the Acutipalpi, &c., and the other 

 Geodephaga. 



