Male.—Head, palpi and thorax entirely black. Abdomen black with a very narrow white ring at the posterior edge of the second and fourth segments Anal tuft black. Legs black, with the hind tarsi dirty white. Fore wings transparent, with black borders and a broad black transverse mark. Hind wings transparent, with a narrow black margin. Under side of fore wings washed with golden yellow, basally. Hind wings same as above. Expanse, 20 mm.

The larvæ are universally borers, but in the choice of food-plants there is the widest diversity; some bore through and devour solid wood, as do the larvæ of the Cossids; some prefer the pith of woody stems; others are found in the superficial woody layers; still others affect the roots of plants both woody and herbaceous, or are sometimes to be found in the borings made by other insects, as is the case with Memythrus tricinctus, Sesia pictipes, S. scitula, and others. The larvæ are yellowish or dirty white, beset with only a few short hairs. The head and cervical shield are chestnut brown. They hibernate in various stages of growth, but do not overwinter in the pupal stage, as far as the species of the northern States are concerned. The larvæ of Melittia satyriniformis hibernate fully grown in the cocoons. When fully developed they spin elongate oval cocoons composed of chips cemented together by a gummy secretion or silk. The cocoons are formed in the burrows or in contiguous places.

Egg. —Pale green, almost globular; very similar to that of Everyx myron, but smaller. Young larvæ collected at Greenwood Lake, New Jersey, June 25th. Length, 1 mm.

Stage I.—Pale apple-green, with numerous minute white dots and a narrow white subdorsal stripe along each side, beginning at the anterior part of the first segment and running to the base of the caudal horn, which is black, and brown at the base. Length, 9 mm. Moulted June 28th.

In answer to Dr. Butler's comments (Can. Ent. XXXI., p. 19) upon my revision of the species of Euchloé (Bull. Am. Mus. Nat. Hist., X., pp. 235-248), I could state that Dr. Butler may possibly be right in considering creusa (var. elsa), hyantis and lotta seasonal forms of ausonides, but with the present knowledge it is not possible to place them so, and for this reason I concluded it would be best to allow the species to remain distinct until more light could be obtained on the subject. At any rate I was certain that what we had labeled in our collections as creusa was not Doubleday and Hewitson's species, which Dr. Butler definitely asserts is my var. elsa.