2/0 INDIRECT BENEFITS DERIVED FROM INSECTS. 



than the species of the genus Cantharis. Preysler iir- 

 forras us that the grub o^C.fusca destroys-a great many 

 other larvae % and I have observed the imago devour 

 these and also Diptera. — Liiine has with justice deno- 

 minated the Cicindelcc 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 ^ny 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, 

 which 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^". 

 This last apparatus, according to Clairville, serves the 

 purpose of an anchor for retaining them at any height 

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

 least the Gyrini and Dytisci, prey upon other insects 

 both in their first and final state. The larva; of the lat- 

 ter have long been observed and described under the 

 Barae of Squillcs, and are remarkable for having their 

 mandibles 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 as by suction. — Another tribe of this order which 

 abounds in species, the Carabidcey is universally insec- 



» Preys. Bomisch. InseJcl. 59. 61. " Plate XVII. Fig. 13. 



'^ Enlom. IlelvcliqueyU, IbH. 



