THE sunrAMii.v imkuinai:. 1037 



the stream, iimuii<;st the damp Kravcl, n beautiful ornufje-coloured llower with a white 

 eentro, about teu oentlniotros in iliameter. The straii-reiiess of the occurrence led uie 

 to step nearer lu ortler to observe It more closely, when what did I see? — the llower 

 consisted of two concentric rlnjts of butterlllos (Callldryas scyllaLlnn.), which had 

 closed their wlnjjs (which are yellow, and orange beneath), and were busily sucking up 

 the moisture from the ilanip sand, and thus represented In the most closely deceptive 

 manner the petals of a Mower. They surrounded live of another white species of 

 Pieris sliriilarly occupied, which thus seemed to form tlie white centre of the (lower. 

 1 still ri'uiember tlie ama/.ement of my travelling conipanlon. when on my nearer ap- 

 proach tlie whole Mower dissolved Into a swarm of butterMies. 



It was pr(>l)alily I'ierliuie. or principally InitterMios belonging to tliat subfamily, 

 which surprised and delighted Mr. K. L. .\rnold In Southern India, on one of his ex- 

 cursions In the dry season. He graphically relates that he "came upon a quiet nullah 

 meandering through the jungle. The bed, by chance, just there was broad and sandy, 

 and the stream a single thread that seemed every moment In danger of vanisliing. 

 But to my astonished eyes the whole place appeared a garden of flowers of a thousand 

 colours, and crowded so close by the water that thcsand could scarcely be seen. I looked 

 and looked again, and then stepped down to observe the parterre closer; but as I 

 did so these animated blossoms sprang into the air in a huge cloud, .and the truth was 

 plain that they were a countless host of thirsty butterflies, collected from the forest 

 all round to drink at this thread of liquid." (Khopalocera Malayana, 284-285.) 



Perhaps partly in consequence of these habits of assembling, but more 

 probably from some immunity from attack,* no other subfamily of butter- 

 flics presents so many instances of swarming propensities, of actual migra- 

 tions and of destructive tendencies, none where the individuals of a species 

 are so generally niuiierous. They are the only foes to our vegetable gar- 

 dens, wliirli is the more marked as the caterpillars of the injurious species 

 do their work for the most part ■■singly and not in companies. As this 

 to()ic will l)e referred to at length in an excursus, a few pages further on, 

 and will be illustrated at several points within the subfamily, it need not be 

 further discussed here. It may be mentioned, however, that Wallace 

 suggests that it may be their congregating habits that "lead to their being 

 frecjuently carried off by winds, and it is thus, perhaps, (hat some of the 

 species have so wide a range and offer such perplexing variations." Yet 

 how rarely this is true appears in his paper on the Pierinac of the Indian 

 and Australian region, in which 27SI species are catalogued. Here he 

 finds but six common to these countries and the palaearctic region . These 

 279 are nearly equally distributed between the Indian and Australian 

 regions, a slight preponderance being shown in favor of the former, while 

 less than a scorn arc common to the two districts. 



The eggs arc iiiucli taller tlian l)road, taller than those of any other 

 group of butterflies, even fusiform, and are always vertically ribbed. 

 They are almost invariably laid singly, but sometimes in open clusters. 

 The juvenile caterpillars arc furnished with club-shaped hairs, varying in 



• It is stated (sec Psyche iii : 47) that ninety field was almost clear, but two ducks died 



duek.'< were once turned into a European cab- after an hour. The next morning twenty 



bagc (ielil infested with the caterpillars of were found dead, and alto^^ether fifty-three 



Mancipium brassieae. In one afternoon (he perLuhed. 



