OF ARTS AND SCIENCES. 61 



middle, the head enlarged and giving off the four or five bristle8. 

 There are now jive rows of indistinct black spots, along the body, like 

 those so distinct in Saviia cynthia, but they are not distinctly seen; 

 those of the median row are somewhat diamond-shaped. One was 

 observed while moulting, June 23. Length 15 mm., becoming 17 nun. 

 The larva is more like S. cynthia, as directly after moultiug it is 

 yellowish, and the five rows of black spots are now very conspicuous, 

 the median dorsal ones being more or less diamond-shaped ; but the 

 tubercles and spines are all black. The head is black, but pale on 

 the labrum. 



In this stage, just before moulting, it spins a floor of silk longer than 

 its body, on which to stand, its crotchets being fastened in it during tin- 

 process of exuviation. 



On June 28, at 9 a. m., one had just moulted, having been seen to 

 draw itself out of the crumpled end of its skin. All the tubercles of 

 the two dorsal rows are amber-yellow, except those on the 2d and 

 3d thoracic segments, which are a little larger than the others, and 

 deep orange. The four prothoracic and also the two lateral rows are 

 pale greenish, without any flesh tints. At this time both the head and 

 the prothoracic segment are entirely pale greenish yellow, and the 

 body is deep yellow, like that of S. cynthia, with the black spots very 

 conspicuous ; all the spines, however, on all the tubercles are black. 

 The tubercles * are now much stouter than before, but are not yet 

 spotted on the sides with black, as they are later in this stage. Its 

 length soon becomes from 18 to 20 mm. 



Half an hour later (9.30 a. m.) it had not changed, but by 11 

 o'clock A. M. the four prothoracic tubercles (rather, however, three, as 

 the inner one on the right side is wanting, another malformation) and 

 the 2d or lower lateral row had turned dark, while the upper lateral 

 row had begun to turn dark at the base. The black patches on the 

 sides of the dorsal tubercles had also begun to appear; also the region 

 at the base of the antennae, as well as the clypeus and labrum, had 

 turned pale. 



At 12.45 p.m. the black tints became more pronounced. The 

 prothoracic spines had all turned, as well as the two lateral ones, 

 except those on the 6th abdominal segment, which were .-till pale al 

 the end. In the 1st or upper lateral row the tubercles were pale at 

 the end. Of the two dorsal rows, those of the abdomen are lemon- 



* One tubercle on the left side of the 3d abdominal segment lias DO spines, a 

 malformation never before observed. 



