THE CANADIAN ENTOMOLOGIST. 47 



more rounded at the top, shining black at the base, and resembling white 

 glazed porcelain at the apex, with four black spines. The next two are 

 smaller, about 2J-4 mil. apart on the front edge of the segment, the 

 lower of which is about 5 mil. from No. 2. These are very small and 

 black, the upper one having a trace of greenish-white at the apex, and 

 both are surmounted with several short black spines. The lowest tuber- 

 cles on segments three to six inclusive are small with black bases, apices 

 resembling white glazed porcelain, and generally two black spines. The 

 tubercles of the next row above, extending from the third to the last seg- 

 ments inclusive, are very similar in form and color, but larger ; those of 

 the row above this are slightly pear-shaped, a very little thickened towards 

 the outer end, of the same color as the preceding, and surmounted with 

 from four to six short stout black spines. Those of the next row on the 

 third, fourth and fifth segments, and the corresponding ones en the oppo- 

 site side of the dorsum — by far the largest on the larva — are pear-shaped, 

 largest outwardly, porcelain white at the base, with a band of shining 

 black above, and a bright coral-red top, with from six to eight stout black 

 spines. The tubercles of this row on the sixth to the eleventh segments 

 inclusive are nearly as tall, but slimmer than those preceding, slightly 

 curving backward, porcelain white at the base, a very light straw color 

 above and armed with two black spines at the top. The dorsal tubercle 

 of the twelfth segment is very similar, but larger, and armed with several 

 black spines. The tubercle at the base of the anal proleg is smaller than 

 those before it, of a light bluish color, with black at the base outside. 

 The most striking differences observed between P. Columbia and P. 



cecropia, in a brood of the latter raised by the side of the former, are 



first, the smaller size of Columbia at each of the stages ; the mature larva 

 of Columbia is about three inches in length, that of ccovpia about four 

 Secondly, Columbia is of a clear light pea green color, ceavpia a dull bluish 

 green, giving a much darker aspect to this larva. This distinction of color 

 is so marked that if once observed, the one can never be mistaken for the 

 other. Thirdly, Columbia has three pairs of coral-red tubercles, one pair 

 each on the third, fourth and fifth segments ; cccropia has two pairs, one 

 pair each on the third and fourth segments. Then the color of these 

 differ; those of Columbia are a true coral or vermilion-red, while all the 

 cecropias I have seen have these tubercles a color somewhat approximating 

 that of resin. The remaining dorsal pairs of tubercles to the twelfth seg- 

 ment, and the central one on the twelfth, are lemon yellow, while in 



