52 



BRITISH BUTTERFLIES. 



land, etc. P. rapae, too, as in Europe, varies in the same manner ; in 

 New England, Scudder says that it is triple-brooded. Our three British 

 species are, in this country, usually partially double-brooded, in very 

 cold summers they may be purely single-, and, in exceptionally hot 

 summers, almost entirely double-, brooded. In the south of Europe 

 they are even partially triple-brooded, but at high elevations and 

 latitudes only single-brooded. The larva of Pieris callidice, however, 

 which has, to some extent, a Pontiid facies in its imaginal stage, is 

 single- brooded, as might be expected, from the high altitudes at which 

 it is always found, the length of summer in its habitats being altogether 

 against the formation of even occasional "forward" habits. Edwards 

 notes that P. sisymbrii, a close Nearctic ally of this species, is also 

 single-brooded, the larvae not developing any " forwards." 



The Pontiids are, larvally, a very intermediate group, with habits 

 perhaps rather more strongly approximating to those of the Antho- 

 carids than to the Pierids. Like the latter, they mature very rapidly, 

 and are almost always solitary in their habit in nature. Our only well- 

 known European species is Pontia daplidice. Although, when young, 

 the larvae eat holes in leaves or flowers, yet, later, they certainly seem 

 to prefer flowers, and, like the larva of Anthocaris belia, love to lie 

 stretched along the stem of the foodplant during the day, rarely moving 

 their position during this period, and, whenever we have found the larva 

 in nature it has been singly, only one larva on a stem or even plant. 

 In its resting-position the larva of Anthocaris belia is very characteristic, 

 seeming to be nothing more than a slight thickening of the stem of 

 Biscutella laevigata, on a cursory glance. Buckler notes (Butts., i., 

 p. 22) that, in confinement, he found the almost fullfed larvae of 

 Pontia daplidice " fond of lying at full length along the flower-spikes, 

 and several crowded together at the summit in amiable companion- 

 ship ; often they would have the head downwards, sometimes with the 

 anterior segments hanging free. Their movements when feeding were 

 slow and very graceful, as their flexible bodies accommodated them- 

 selves readily to any inequality of surface over which they glided; they 

 covered the stems and other parts with fine silk threads, which 

 proceeding rendered their footing more secure. They seemed quite as 

 partial to the flowers as to the leaves, and thus varied their food." 

 P. daplidice is quite Pierid in its habit of producing " forwards," the 

 species being fully double-, and possibly of ten partially triple-, brooded 

 in the more southern part of its range. The larva, however, is a 

 delicate one, and, although the butterfly is continuously attempting to 

 push its way into more northern latitudes, the larval habits evidently 

 prevent it from making a permanent home in the colder parts of the 

 Palaearctic area. The somewhat-allied Nearctic P. protodice also 

 produces "forwards " freely, and is more or less triple-brooded in the 

 more southern parts of its range. Its further larval habits, however, 

 as recorded by Riley, remind one of rather of those of the common 

 Pierids than of those of Pontia daplidice. This observer states that "it 

 appears to confine its ravages more closely to the cabbage than do the 

 other 'white' butterflies, but is occasionally found feeding upon turnip, 

 and does great injury to sweet alyssum, A. maritimwn, etc., com- 

 mencing at the head, and eating down to the base of the plant, whilst 

 it has also been found on mignonette " (Scudder's Butts. New Engl,, 

 ii., p. 1168). 



