FOOD OF INSECTS. 395 



voluted when at rest, like the main spring of a watch, 

 into a convenient compass. This tongue, which they 

 have the power of instantly unrolling, they dart into the 

 bottom of a flower, and, as through a syphon, draw up a 

 supply of the delicious nectar on which they feed. A 

 letter would scarcely suffice for describing fully the ad- 

 mirable structure of this organ. I must content myself 

 therefore with here briefly observing that it is of a carti- 

 laginous substance, and apparently composed of a series 

 of innumerable rings, which, to be capable of such rapid 

 convolution, must be moved by an equal number of di- 

 stinct muscles ; and that, though seemingly simple, it is 

 in fact composed of three distinct tubes, the two lateral 

 ones cylindrical and entire, intended, as Reaumur thinks, 

 for the reception of air; and the intermediate one, through 

 which alone the honey is conveyed, nearly square, and 

 formed of two separate grooves projecting from the lateral 

 tubes ; which grooves, by means of a most curious appa- 

 ratus of hooks like those in the laminae of a feather, in- 

 osculate into each other, and can be either united into 

 an air-tight canal, or be instantly separated, at the plea- 

 sure of the insect a . 



Another numerous race, the whole of the order He- 

 miptera, abstract the juices of plants or of animals by 

 means of an instrument of a construction altogether dif- 

 ferent — a hollow grooved beak, often jointed, and con- 

 taining three bristle-formed lancets, which, at the same 

 time that they pierce the food, apply to each other so 

 accurately as to form one air-tight tube, through which 



* For a full description of this instrument see Reaum. i. 125, &cv 

 Plate VI. Fig. 29, 30. 



