400 



NATURAL HISTORY OF ARTHROPODS. 



FIG. 499. Calosoma 

 calidum. 



FIG. 500. Calnsoma scrutator. 



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

 observed to eat canker-worms (larvae of Anisopteryx), and the larvae of C. externum 

 prey upon army-worms (larvae of Leucania unipuncta) ; in Aus- 

 tralia the larva? of C. curtisii live beneath cow-dung, where they 

 probably feed on noctuid larvae ; and the larvae 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-colored punctures, the rest 

 of the insect being black. Professor 

 A. S. Packard states that he has 

 seen this species attack the June-bug 

 (Lachnosterna fused) and tear its sides open. The 

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

 cies of this genus that inhabits the eastern United 

 States is C. scrutator, which measures a little over an 

 inch in length. The elytra are metallic green, margined 

 with a narrow line of reddish bronze ; the prothorax is 

 deep shining blue with the channel formed by its up- 

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

 of larvae. In Europe C. sycophania resembles quite closely C. scrutator, but lacks the 

 reddish-bronze margins of the prothorax and elytra. 



The species of Cychrus, which are distributed by some authors into several genera, 

 differ from those of Carabus and Calosoma in having the posterior coxa? separated 

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

 of Cychrus are said to be distinguished from those of Carabus by their brown color 

 and by the four teeth with which the last abdominal segment is armed in place of the 

 two horns so common in carabid lai'vae. The generally elongated anterior 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 palpi of these insects appar- 

 ently co-operate with their elongated mandibles in extracting the 

 soft tissues of snails from their shells. C. stenostomus, of which 

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

 is of a bluish-black color. C. elevatus has the posterior angles of 

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

 elevated margin of the anterior part of the coppery-bronze elytra. 

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

 the southward and westward. Its length varies from 0.6 to 1.1 

 inches. The only specimen that I have taken in New England 

 was found in northern Connecticut, eating a species of freshly 

 killed Helix albolabris. The largest species of Cychrus found in New England is C. 

 viduus, which varies from 0.70 to 1.16 inches in length. C. rostratus is found in 

 many parts of Europe. 



The genus Omophron 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 

 elevatus. 



