STATES' OF INSECTS. 151 



larvae of a rose colour. The animal seldom protrudes 

 them, unless in some way disturbed ; and frequently it 

 approximates the two outer cases so closely that they re- 

 semble a single horn. It appears to use these inner horns, 

 when protruded, as a kind of whip to drive away the 

 flies, especially the Ichneumons, that alight upon its body. 

 When touched in any place, it will unsheath one of them, 

 and sometimes both, and with them strike the place where 

 it is incommoded a . A similar organ is found in some 

 other Bombycidce, as B, Tau and Furcula F. Reaumur 

 mentions a caterpillar that to this kind of tail added the 

 resemblance of two ears, or two cylindrical bodies, ter- 

 minating in a point, which emerged from the first segment 

 behind the head b . In another observed by the same au- 

 thor, the legs were replaced by a single horn, but which 

 did not appear to send forth an internal one : from the 

 back of its fourth segment also emerged a single conical 

 or pyramidal fleshy eminence or cleft, terminating in two 

 points c . Some of the tropical butterflies also, as may be 

 seen in the figures of Madame Merian, have two diver- 

 ging anal horns instead of anal prolegs ; but it does not 

 appear that they incase tentacula d . Wherever these 

 caudal horns are found, the above prolegs are wanting e . 



a De Geer i. 322—. See Plate XIX. Fig. 2. a a. 

 b Reaum. ii. 275. t. xxii./. 3. 

 c Ibid. 276. t. xxii./. 4, 5. 



d Ins. Surinam, t. vii. Nymphalis Amphinome xxiii. Morpho Teu- 

 cer t. xxxii. PapUio Cassice. 



e This is not, however, universally the case, for the caterpillar of a 

 Geometer described by Reaumur (ii. 363. t. xxix./. 8.) (G. amatoria) 

 has a pair of fleshy anal horns, terminating, it should seem from his 

 figure, in a minute hook that the animal uses as a forceps; which has 

 at the same time the anal legs, of which indeed these horns seem to 

 be appendages. 



