AS BOTANISTS 61 



usually by but a single species of butterfly, is only 

 what one who has reared butterflies might expect, 

 since he must often have found that under no 

 consideration would a given caterpillar feed upon 

 anything whatever but its own pet food plant. 

 This is more striking because of the polyphagous 

 nature of others, such as Jasoniades giaucus, 

 which feeds upon plants belonging to no less than 

 fifteen different families. 



In many, perhaps the majority of instances 

 the plants upon which allied species or genera of 

 caterpillars feed, themselves belong to allied fami- 

 lies of the botanical systems ; and Fritz Miiller 

 brings forward some curious instances in which 

 a knowled2:e of the habits of butterflies would 

 have led, had they been followed, to an earlier 

 recognition of the affinities of certain plants. 

 Thus he says (Nature, xxx. 240) ; — 



" The caterpillars of Mechanitis, Dircenna, Ceratinia, 

 and Ithomia feed on different species of Solanaceae 

 (Solanum, Cyphomandra, Basso via, Cestrum), those of 

 the allied genus Thyridia on Bninfelsia. Now this 

 latter genus of plants had been placed unanimously 

 among the Scrophularineae, till quite recently it was 

 transferred by Bentham and Hooker to the Solanaceae. 

 Thus it appears that butterflies had recognized the 

 true affinity of Brunfelsia long before botanists did so. 



