THE latest number of the Arxivs de I'Institut de Ciencies, published at Barcelona, contains an excellent monograph of the Chrysopidæ of Europe from the pen of Father R. P. L. Navas, the well-known authority on the order Neuroptera. The present group, sometimes known as Hemerobiidæ, and in this country as “lace-wing flies,” or “golden-eyes,” presents many features of interest. From the point of view of economic entomology its importance rests on the fact that in the larval stage it is a great destroyer of aphids. Unlike the almost stationary larvae of the Syrphids, or hawkflies, which are also of much value as devourers of plant-lice, the Chrysopid larva is able to move actively about from place to place in search of its prey. In this it resembles the larva of the ladybird, another great ally of the agriculturist against the same enemy.