RILEY ADDITIONAL NOTES ON MEGATHYMUS YUCC^. 567 



beneath the ground, and attaining full growth by the end of Sep- 

 tember ; while a third, in a potted Yucca aloifolia in-doors, hollowed 

 out the entire root, pupated on the 26th of January, 1877, and gave 

 out the imago on the 25th of the following month. 



I add the following to complete the description of the larva 

 given on p- 331 : 



In the second stage (after first molt) the head is deep gamboge-yellow, 

 with dark jaws — not polished but faintly shagreened : the cervical shield is 

 narrow, entire, and polished black; and an anal plate is also obvious, also 

 polished, dark brown, with the hind borders thickened and black. The 

 body is olivaceous-brown ; the stiff, black hairs of the first stage are very 

 much shortened and pale, and the whole surface has a faintly pubescent 

 appearance, caused by numerous minute points, each giving rise to a short 

 sofl hair. The wrinkles of the mature larva are already well defined. In 

 the third stage the head is chestnut-brown, and the stiff, piliferous hairs 

 are scarcely longer than the other minute ones on the general surface. 

 The larva has now all thecharacteristicsof the last stage, except in lacking 

 the white powder, and in being of a pale olive-brown color. The cervical 

 and anal shields are still highly polished and black, and the skin, instead 

 of looking faintly pubescent, as in the previous stage, is translucent and 

 glossy. 



The imago is more variable than I had supposed. Thirteen 

 other specimens, all from larvae that fed at Bluffton, S. C, range 

 in expanse from 1 4 to nearly 3 inches ; 2 ? 's have the wings 

 broader and the posterior border of primaries more rounded than 

 is usual, resembling ^giale in this respect : i ? has the spot 

 (usually lacking) on primaries just within the middle of the wing 

 and below vein 2 ; while in 2 c?'s, and among them that which I 

 bred in-doors, the yellow is pale almost to whiteness. Some spe- 

 cimens, captured in Florida by Mr. A. Bolter of Chicago, expand 

 only I \ inches, and the secondaries have five such distinct yellow 

 spots and such broad yellow borders that they look two -banded. 

 Mr. H. K. Morrison captured many specimens in Colorado, the 

 past summer, about Yucca angustifolia, and this Colorado form is 

 remarkable for its small size and the paleness of its colors com- 

 pared with those reared farther south on the larger-leaved, more 

 luxuriant Yuccas. It is also distinguished by a second narrow 

 white line on the underside of secondaries just outside the larger 

 triangular white spot from costal vein ; also by the dark spots on 

 this underside of secondaries, generally having a white pupil — a 

 tendency thereto being noticeable in the Carolina specimens. I 



