"Timon [aside]. Nor more willingly leaves winter; such summer-birds are men;"

and T. and C. iii. 3:

"For men, like butterflies,
Shew not their mealy wings but to the summer."

Mitford suggests that Gray had in mind Horace, Od. i. 35, 25:

"At vulgus infidum et meretrix retro
Perjura cedit; diffugiunt cadis
Cum faece siccatis amici
Ferre jugum pariter dolosi."

[25.] In sable garb. Cf. Milton, Il Pens. 16: "O'erlaid with black, staid Wisdom's hue."

[28.] With leaden eye. Evidently suggested by Milton's description of Melancholy, Il Pens. 43:

"Thy rapt soul sitting in thine eyes;
There, held in holy passion still,
Forget thyself to marble, till
With a sad leaden downward cast
Thou fix them on the earth as fast."

Mitford cites Sidney, Astrophel and Stella, song 7: "So leaden eyes;" Dryden, Cymon and Iphigenia, 57: "And stupid eyes that ever lov'd the ground;" Shakespeare, Pericles, i. 2: "The sad companion, dull-eyed Melancholy;" and L. L. L. iv. 3: "In leaden contemplation." Cf. also The Bard, 69, 70.