LARVA. Food plant, _Opuntia missouriensis_, prickly pear cactus, burrowing into the fleshy leaves and eating the soft, succulent, inner tissues. Length, 40 millimeters. Five pairs of prolegs. Color, one specimen, ultramarine blue; skin, semi-transparent and shining anteriorly, dead blue on dorsum; second specimen, buffy with a bluish suffusion, blue between segments, prolegs bluish, and last abdominal segment blue, especially below; skin more opaque than in first specimen. No pronounced markings of skin; spiracles shining black and present on first thoracic and first to tenth abdominal segments. Head flattened, slightly narrower than first thoracic segment, umber. Prothoracic shield well marked, brownish black; anal shield, smoky brownish. Clothing, limited to tubercled hairs sparsely distributed as follows: a subdorsal line of small tubercles, two tubercles to a segment, each tubercle bearing three short, fine hairs; a supra-stigmatic line, one tubercle to each segment, each tubercle bearing three to four fine hairs; a similar infra-stigmatic line; a sub-ventral line of tubercles, bearing usually four fine hairs, the tubercles of the three thoracic segments in this line situated at base of legs outside, and similarly as to the prolegs on the third to sixth abdominal segments. The tubercles in all the lines are faintly smoky. The larva is rather heavy, and rotund in form, tapering toward both head and posterior segment. It moves with a lumbering gait, but rather rapidly. CHRYSALIS. Length, 20 millimeters; in cocoon of silk, loosely covered with small dirt-masses. As made in the breeding cage the cocoons were above ground, but concealed under or in available objects.