249) NOCTUID LARVAE— RIPLEY 



INTRODUCTION 



The principal object sought in this work is to investigate the value of 

 certain more or less neglected lines of evidence as a source of phylogenetic 

 information. Such evidence has been applied to the Noctuidae for the 

 purpose of throwing light upon our knowledge of the structural and biolog- 

 ical relationships within the family. It has also been our aim to perform 

 the necessary studies preliminary to the making of natural tables for the 

 identification of noctuid larvae. 



There are four kinds of evidence contributing to our knowledge of the 

 phylogeny of animals: comparative anatomical, recapitulative, paleonto- 

 logical, and biological. Heretofore the systematic entomologist has con- 

 cerned himself almost entirely with the first of these, the second remaining 

 either uninvestigated or uninterpreted, the third presenting a relatively 

 scant amount of material, and the last offering a virtually untouched field 

 of somewhat uncertain possibility. Not only has the worker on the taxon- 

 omy of insects practically confined himself to anatomical evidence, but he 

 has, until quite recently, based his classification solely on the structure of 

 adult insects. Within the last decade a few excellent researches on the 

 classification of immature insects, such as Tracker's upon lepidopter- 

 ous larvae, Howard, Dyar, and Knab's upon mosquito larvae, Edna 

 Mosher's upon the taxonomy of lepidopterous pupae, and Malloch's 

 studies upon immature Diptera, have demonstrated beyond a doubt the 

 value of a morphological study of immature insects as a source of phylo- 

 genetic information. 



The study of the ontogeny of insects may be conveniently divided into 

 embryology and postembryology. The latter deals with development after 

 hatching from the egg. It regards the larva as a free-living embryo, and 

 the pupa as representing a highly specialized stage corresponding to a 

 larval stadium. We may, then, speak of larval or pupal postembryology. 



Since the earlier embrj-onic stages of insects must recapitulate, so far 

 as the law is manifested, conditions in phylogeny prior to the appearance 

 of insects, the taxonomist must look to the older embryonic stages, which 

 have usually not been studied, and to the postembryonic development for 

 recapitulative e\'idence. As might be expected from their highly adaptive 

 nature, pupae reveal the working of recapitulation to a less marked extent 

 than do larvae. Comstock, however, based his hj^pothetical ancestral 

 wing venation upon the pupal wing of Hepialus, and Dr. Edna Mosher 

 found that certain wingless female moths have pupal wing-pads. In 



