Summary

The cosmopolitan and economically important genus Platyptilia is represented in California by 22 species, or 71 per cent of all those recorded in the United States. The present work describes all of the species and the many subspecies known to exist in this state; and further, it establishes three new species and four new subspecies of the genus.

Platyptilia baueri

Platyptilia lutescens

Platyptilia bifida

Platyptilia pica calisequoiae

Platyptilia pica marina

Platyptilia pica sierrae

Platyptilia albiciliata rubricans

The California moths formerly placed in the European species, Platyptilia acanthodactyla and P. punctidactyla, were found to be referable to P. pica.

In this study the emphasis has been placed on the immature stages as an aid to evaluating properly the morphological characters of the adults. Larvae or pupae of many species were collected on larval food plants, and raised to adulthood. It was found that the divergences noticed in the immature stages are reflected in like divergences in the characters of the adults.

Contrary to the belief of many previous workers, it was found that the male genitalia exhibit good characteristics for specific differentiation, and that the female genitalia of the California species are of great value in certain instances.

The California species of Platyptilia showed two major trends of speciation toward adaptation to food plants, one to the family Compositae and the other to the family Scrophulariaceae. Members of the group associated with the Compositae were found to be distinct biologically and morphologically from those of the group feeding on the Scrophulariaceae. Although the biological features of this relationship have not been completely explored, these studies suggest that on a morphological basis one can predict the family of plants to which a given species can be assigned. This will aid the future study of the biological relationships of the group.