INSECTS EMPLOYED IN MEDICINE, OR AS FOOD. 97 



tubercles, rudiments of feet. The third larva bears 

 a strict resemblance to the second larva. From this 

 stage the usual metamorphoses of insect life begin, 

 and follow out their ordinary course : this third larva 

 becomes first a chrysalis, from which it emerges as 

 a perfect insect. 



Other coleopterous insects are endowed with 

 inflammatory or blistering properties. Such, for 

 instance, is the Cetonia aurata, or golden beetle, 

 which was employed in the time of Pliny, and which 

 plays such an ingenious part in the tale of Edgar 

 Poe. Such again are the Goccinella, or lady-birds, 

 which, when captured, secrete from their legs an 

 acrid yellow fluid having a disagreeable odour. 

 It is doubtless to this fluid that they owe their 

 property of curing the most violent toothache when 

 they are placed alive in the hollow part of the 

 tooth. 



A pharmaceutical substance, known as Trehala, 

 has lately been studied by M. Guibourt. It is a 

 kind of insect-nest or hollow cocoon, round or oval, 

 about the size of a large olive, and is the produce of 

 a coleopterous insect (or beetle) closely allied to the 

 genus Curculio, and named Larinas nidificans. This 

 insect lives on the branches of a shrub, a species of 

 Echinops. 



The trehala is composed of 66 '54 parts of starch, 

 4'66 of a kind of gum, and 28'80 of sugar, mixed 



H 



