Blooms of prickly pear and cholla cacti decorate the deserts around Tucson.

The milky white flowers of saguaros, yellow blooms of prickly pears and other kinds of cactus are arriving just in time to fill a void left by gradually fading wildflowers.

THE note in NATURE of June 27, p. 989, on the eradication of prickly pear in South Africa suggested that information about the use of Dactylopius tomentosus in the tropics might be of interest ...