One summer day"" a bright orange butterfly skims over the meadow--and, in the (otherwise) black-and-white pictures, a dog pursues it, kids ponder it, dance with it, play with it. . . until it takes off again, in the same words, on the last double-page spread. An endless chase then, a perpetual gambol--in illustrations, combining A. B. Frost tetchiness and Susan Perl preciousness, that are as devoid of conviction as what they illustrate.