18 



INSECTS OF SAMOA. 



and no connecting forms nave yet been described ; the intervening islands 

 are, however, so little known that it is quite possible that such forms exist 

 on them, but have not yet been met with. 



The egg is barrel-shaped, 1*6 mm. in height and 1*0 mm. in diameter, pale 

 yellow, with some twenty-four longitudinal and about the same number of 

 transverse ribs dividing the surface up into roughly rectangular areas, which 

 are more irregular towards the apex. The shell is particularly soft, and the egg 

 is easily crushed. The ova are laid singly on the upper or underside of a leaf 

 of the food-plant, Ficus tinctoria Forst., a common bush which grows either 

 as an epiphyte in the crowns of Pandanus and other trees, or as an independent 

 plant. The butterfly is not strictly confined to this species, but sometimes 

 selects other members of the genus Ficus. ■ 



The larva spins a pad of silk on the leaf to improve its foothold. When 

 young it is green, with a pale yellow sub-spiracular line ; head, legs, prolegs 

 and two pairs of fleshy filaments, one on the mesothorax, the other on the 

 eighth abdominal segment, are black. The full-grown larva (PL IV, fig. 3) 

 is about 30 mm. long, and varies considerably in colour ; the form found 

 invariably in a wild state has the body, legs, and prolegs glaucous-green ; the 

 head is pale brown, with two pale green lines ; there is a broad pale yellow 

 sub-spiracular line, and the spiracles are black ; the fleshy filaments, which are 

 large in proportion to the size of the larva, are purplish-brown in colour. When 

 larvae are reared in captivity, either from eggs or from very young caterpillars, 

 the commonest form when full-grown is very dark, almost black, with a yellow 

 sub-spiracular line and black filaments ; a modification of this form has the 

 head black, the body above the yellow sub-spiracular line deep black with 

 one rather broad and three broken and rather narrow white transverse bands 

 on each segment, and spiracles, filaments, legs and prolegs black. Almost all 

 larvae in captivity are of one of these dark forms, unless captured when already 

 half-grown. A parallel case is that of Macroglossa hirundo samoana Roths, 

 and Jord. (Sphingidae) ; here, also, there are two main types of coloration 

 in the larva, one of which is green and the other dark. The dark form varies 

 considerably, but is more or less as follows : brown-red above, under surface 

 dark brown approaching black ; head, legs, and prolegs black ; blackish mid- 

 dorsal and supraspiracular lines, the space between these lines broken up into 

 square blocks of brown-red by dark brown intersegmental lines ; spiracles 

 black ; whole of upper part of body thickly covered with small white dots ; 



