Aphids on Deciduous Trees

Aphids are tempting subjects for investigation because they are often abundant, easily found, and unlikely to run away, and because of intriguing facts about their biology such as polyphenism, parthenogenesis, gall formation, and the production of a soldier morph. However, until now identification has presented a severe challenge to the beginner, because there are so many rather similar species, many of which have several different forms. The authors make this much—needed Naturalists' Handb...