'268 INDIRECT BENEFITS DERIVED If ROM INSECTS. 



other larvae 3 , and I have observed the imago devour 

 these and also Diptera. — Linne has with justice denomi^ 

 nated the Cicmdelce the tigers of insects. Though de- 

 corated with brilliant colours, they prey upon the whole 

 insect race ; their formidable jaws which cross each other 

 are armed with fearful fangs, showing to what use they 

 are applicable; and the extreme velocity with which 

 they can either run or fly, renders hopeless any attempt 

 to elude their pursuit. Their larvae are also equally 

 tremendous with the imago, having six eyes, three on 

 each side, seated on a lateral elevation of the head, 

 winch look like those of spiders, and besides their threat- 

 ening jaws armed with a strong internal tooth, being 

 furnished with a pair of spines resembling somewhat the 

 sting of a scorpion, which stand erect upon the back of 

 the abdomen, and give them a most ferocious aspect b . 

 This last apparatus, according to Clairville, serves the 

 purpose of an anchor for retaining them at any height 

 in their deep cells c . Most of the aquatic beetles, at 

 least the Gyrini and Dytisci, prey upon other insects 

 both in their first and final state. The larvae of the latter 

 have long been observed and described under the name 

 of Squillcs and are remarkable for having their mandi- 

 bles adapted for suction like those of Hemerobius and 

 Myrmeleon ; but they are not like them deprived of a 

 mouth, being able to devour by mastication as well os 

 by suction. — Another tribe of this order which abounds 

 in species, the Carabidce, is universally insectivorous. 

 One of the most destructive is the grub of a very beauti- 

 ful species, an English specimen of which would be a 



* Preys. Bomisck. Inseht. 59. 61. b Plate XVII. Fig. 13, 

 c Entam. Helvetiquc, ii. 158. 



