The genus Agrotis embraces moths of medium size as a rule, and many of them of the typical "Owlet" type. The caterpillars of many of the species are very injurious to cultivated plants, and come under the head of "Cut-Worms," a name given them from their habit of cutting off, just at the surface of the ground, the plants upon which they feed. The genus Agrotis, our American species alone considered has but to characters common to all forms: the eyes are naked and the middle and posterior tibiae are always spinose!
In a 13 page preface, Smith lays out a lengthy explanation of the origin and purpose of this catalogue of the moth family Noctuidae in the United States. In short, he collected materials over a span of ten years for a monograph on Noctuidae, including material from books from Philadelphia, New York, Washington, as well as purchasing subject papers when available. His efforts included reviewing specimens within the National Museum, as well as trips abroad. Many of the individual species notes contain multiple bibliographic citations that are tersely abbreviated in the extreme. Fortunately, Mr. Smith has also provided an Index to the Authors and Works Cited to help decipher the citations.