Snail-eating Beetles. 269 



to enable him the better to pursue it. iMost of these ground-beetles, which 

 probably are all carnivorous, have neat and graceful forms ; but the cvchrus 

 has its head and fore-bod}' made so slender that it can reach some distance into 

 a snail-shell should the snail retreat within when the cychrus makes a call. 



But probably the reader will lind greater interest in the little-known drilus,^ which 

 must be sought on chalk downs and similar places where the heath-snail, the banded- 

 snail, and the wrinkled-snail are plentiful. The reason for the greater interest 

 yielded by this beetle is due to the fact that its life-historv was carefulh* worked 

 out a few years ago by Mr. L. R. Crawsha\', 

 .M.A., and the story communicated to 

 the Entomological Society of London. .^ 



That drilus was an enemy to snails had 

 been known for man}^ years ; but full 

 details of its life had been wanting. As 

 in the case of the glow-worm, the female 

 never attains to the orthodox beetle- 

 form, and remains to the end of life but 

 little changed from the appearance she ^^''"^° '^-'^ Snail-eating Beetle ^^ ^^'^^' ^^^' 



presented in the grub-stage. The male, a good example of adaptation of structure to habits is seen 



, . 1 • 1' 1 V 1 -1 among ground-beetles in cvchrus, which is here photographed. 



llOWeVer, is a true little beetle with The fore-body is greatly reduced in width and the head is 



.. . . . . .. . lengthened to enable the beetle to push its fore-parts into the 



\'ellOWlSh- brown wing-cases, with wings shells of snails, upon which it chiefly preys. 



beneath them, and a pair of much-branched long antennae. To the beetle 

 collector he appears to be much more plentiful than his mate, but Mr. Crawshay 

 found as a matter of fact that the males are few as compared with the 

 females. The difference in the form of the two sexes will be appreciated b\- 

 a glance at the foreground figures in the drawing we have had made on a scale of 

 five times the actual life size. In this drawing the upper figures on the snails 

 are all grubs. 



Viewed from above, the grubs are seen to be tapered somewhat from back 

 to front, and are covered with flesh}^ growths from which spring coarse hairs of 

 a red-brown colour. The head also is red-brown, and flattened ; the mouth armed 

 with strong sharp mandibles. At the end of the hind-bod v there are two bristly 

 outgrowths, which are evidently for the protection of the grub when it is in the 

 snail-shell, keeping off any enemy that would otherwise attack it from the rear. 

 The grub begins life about the middle of Julv, and does not become a beetle until 

 the early summer of the third or fourth vear. 



Its mode of procedure when about to attack a snail, as obser\'ed bv 

 Crawshay, is curious. It is deliberate in its actions, and docs not begin bv 

 poking its nose into the first snail-shell it comes across. First, the grub 

 climbs upon the shell, and examines it to satisf}' itself that it contains 

 a snail. But perhaps the snail is not suitably situated to afford drilus a 

 safe and uninterrupted meal — for this is not to be one of the quick- 

 lunch kind, but extended over many days. If the snail is not so placed as to offer 

 a quiet time, the beetle-grub pushes it into a more favourable position, probably into 

 cover of some sort. This is often a difficult matter, for the snail ma\- recpiire lifting over 



^ Drilus llavescens. 



