☞ Besides the true males and females, there is a race of wingless asexual individuals which have the power of producing living young in rapid succession, and these in turn may produce others of the same kind for several generations, before sexual individuals appear. They suck the sap of plants by means of a tubular proboscis, and owing to the wonderful rapidity of their reproduction become very destructive to vegetation. Many of the excrete honeydew from two tubes near the end of the body.