400 



NATURAL HISTORY OF ARTHROPODS. 



Fig. 499. — ( 'alosoma 

 calidum. 



■ Cnlnsnmn arrnttltor. 



Carabus. In the United States Calosoma calidum and C. srrtitator have been 

 observed to eat canker-worms (larvae of A}ii«opteri/a-), and the larvaj of C. externum 

 ])rey upon arniy-wonns (hirvsfi of Leiicania unijiuncta) ; in Aus- 

 ti-alia tlie larva' of C. oirtisii live beneath covtf-dung, where they 

 probably feed on noctnid larvoe ; and the larvte of several species 

 of Calosoma devour snails. The commonest species of this genus 

 in the eastern United States is C. 

 calidum., which is about an inch long. 

 Its elytra are covered with large 

 bronze-coloreil punctures, the rest 

 of the insect being black. Professor 

 A. S. Packanl states that he has 

 seen this species attack the Jnne-l)Ug 

 {Lachuostvriia /i/.sca) and tear its sides open. The 

 larva of C calidinii is black. The most brilliant spe- 

 cies of this genus that, inhabits the eastern United 

 States is ('. scrutator, which measures a little over an 

 inch in length. The clyna are metallic green, margined 

 with a narrow line of riMldish bronze;- the protliora.x is 

 deep shining blue with tlu' channel formed by its up- 

 turned edges paved with reddish bronze. This species is said to climb trees in search 

 of larvfe. In Europe (J. sj/coj^hiuita resembles (juite closely C. scrutator, but lacks the 

 reddish-bronze margins of the prothorax and elytra. 



The species of (_'i/chrus, which are distributeil by some authors into several genera, 

 differ from those of f'arabus and (_'o/osoma m hnvmg the posterior coxre separated 

 and the labrum bifurcate. The antcmup have four basal joints glabrous. The larvae 

 of Ci/c/iriis are said to be (bstinguished from those f>f Carabus by their brown color 

 and by the four teeth with which the last abdominal segment is armed in ]>lace of the 

 two horns so common in caraliiil larviv. The generallj^ elongated antei'ior parts of 

 these beetles well fit them for their mode of life, enabling them to reach deeply into 

 the shells of snails, on which they feed. The flattened, often 

 broadly triangular apical joints of the j)al]ii of these insects appar- 

 ently co-o])erate with their elongated mandibles in extracting the 

 soft tissues of snails from their shi'Us. ('. stenostomus, of which 

 C. lecontei is a variety, is found in the eastern United States, and 

 is of a bluish-l)lack color. C. clcratus has the ]iosterior angles of 

 the black thorax margined, and the margins elevated to meet the 

 elevated margin of the anterior ]>art of the coppery-bronze elytra. 

 This beautiful species is rare in New England, but more common to 

 the southward and westwai-d. Its length varies from 0.6 to 1.1 

 inches. The oidy sjiecimen tjiat I have taken in New England 

 was found in northein Connecticut, eating a species of freshly 

 killed Helix albolabris. The larm'st s])ecies of Cijchrus found in New England is C. 

 mdu us, -which varies from (i.7(i to l.lfi inches in lengtli. C. rostrntus is found in 

 many jjarts of Europe. 



The genus Omojihron includes a small number of flattened, nearly round beetles, 

 which live in moist places. The anterior coxal cavities are closed behind, the proster- 

 num is prolonged and dilated so that it entirely conceals the mesosternum, and the 



Fig. 501. — Cychrus 

 elevatiis. 



