( Ixv ) 



hypothesis did not provide the true interpretation of the dis- 

 tasteful qualities of many butterflies and moths with warning 

 colours. It was indeed probable, although he believed it had 

 never been proved, that the ready-made acid or poisonous 

 substances of a food-plant might be utilised by the larva and 

 retained in the imago of certain species; but such qualities 

 could also be built up in the laboratory of the animal's body 

 by insects feeding upon innocuous plants. Among the 

 examples quoted by Haase, the Danainae feeding on Asclepiads 

 and the Pharmacophagus swallowtails on Aristolochias and 

 their allies, were probable examples of the utilisation of a 

 ready-made protection. On the other hand, Dr. 0. Stapf, 

 F.R.S., had informed him that the Passifloraceae, the food- 

 plants of the Heliconinae and their allies are not, as Haase 

 maintained, acrid or poisonous. 



Mr. W. A. Lamborn had shown in the last few years that 

 Acraea larvae of many species, in the Lagos district, feed on 

 a great variety of plants, thus rendering it improbable that 

 Haase's hypothesis applies to them. 



The Pierine genus Delias had recently occurred to Prof. 

 Poulton as a specially significant example. These highly 

 conspicuous butterflies had been shown to be distasteful, and 

 they were well known to be mimicked by other Pierines 

 (Prioneris), by Elymniines and by moths (Chalcosiinae). 

 Furthermore, the larvae of some species at any rate were 

 gregarious, and in some the conspicuous pupae were freely 

 exposed on the larval web. Mr. E. E. Green had observed 

 that the larvae of a Ceylon Delias emitted a strong smell of 

 musk. Now, so far as we know, the species of Delias feed 

 upon the Mistletoes (Loranthaceae), which, Dr. Stapf informed 

 him, possessed no special acrid or distasteful qualities. Mr. 

 H. N. Ridley, F.R.S., had also found the leaves of Loranthus 

 always indifferent to the senses of taste and smell. The 

 extraordinary development of Delias in New Guinea led Prof. 

 Poulton to inquire whether there was any special predomi- 

 nance of these plants in the island or in the Malayan region 

 generally. Dr. Stapf had kindly replied as follows : — 



" The Loranthaceae are generally well represented in the 

 Malayan region as far as the number of species goes, and that 



PROC. ENT. SOC. LOND., III., IV. 1916 E 



