雙丫髻 Hair In Two Twin Tufts
嚶的一聲，一翅飛離了妖精，轉向前路，有十數里地，搖身一變，又變做一個道童：嘤的一声，一翅飞离了妖精，转向前路，有十数里地，摇身一变，又变做一个道童：
逐句解 Line by line
With a buzz he beat his wings and flew clear of the fiend, went on down the road ahead a good ten li and more, and with a shake of his body changed again, into a Daoist novice:
嚶的一聲 puts the insect's noise before the insect moves — the same order the gong took a scene ago, and the third time in this chapter that something announces itself by sound before anyone sees it. 十數里 is some ten li: 數 at shù makes the figure approximate, the way English says a dozen or so.
Hair caught up in a pair of twin tufts; a robe of a hundred patches on his body.
The set-piece runs to two lines of five and five, twenty characters in all — the shortest in the chapter. Both line-ends rhyme, on 衣 at yī and 詞 at cí. The two sat in one rhyme group in the older books and split apart in the later ones, so this is a vernacular ear at work rather than a strict scheme.
In his hand the fish-drum and the clappers; in his mouth a lay of the Way.
魚鼓簡 are the fish-shaped drum and wooden clappers a wandering Daoist begs and performs with, and 道情詞 is the ballad form he performs — busking repertoire, essentially. Both halves of the line name the instrument first and the man second, so the whole disguise is assembled out of props.
Twenty characters is a small budget for a costume and every one is working. Two tufts of hair and a patched robe make the novice; a drum, clappers and a ballad make him a busking one. Nothing describes a face, and nothing needs to — the point of this disguise is that it explains why a stranger would be on the road at all.
The last of the four props is the one that pays off. A wandering Daoist who sings for his supper is exactly who a bored demon king would send for, and the courier will suggest it himself before the scene ends. Wukong has built the invitation into the costume before he knows he is going to need it.