Synoptic Notes on Some Nearctic Limnephilid Caddisflies. (Trichoptera, Limnephilidae)

Abstract

In a general survey of the caddisflies belonging to the family Limnephilidae, two general conditions are apparent. The first is that many genera in various sections of the family are either poorly delineated or are diagnosed in existing keys on characters which are proving unreliable. In spite of this, few workers go far astray in placing species in various genera, nor is there a tremendous amount of radical disagreement as to the species composition of many genera which come in the above category. In most of these genera, both sexes have distinctive types of genitalia and it seems obvious that most workers have been placing species in these genera on the basis of the type of genitalia rather than by strict adherence to the spur count and venational characteristics on which the genera are theoretically based. A study of the genitalia throughout the Limnephilidae has convinced me that in many parts of the family the general type of genitalia is of more phylogenetic and diagnostic importance than characters of the wings and legs. Characters of the genitalia are illustrated in this paper for several obscure genera. The second item of interest in the family involves the extremely interesting distribution patterns which are becoming evident, especially in the groups of species occurring to the north and in the various ranges of the western mountains. Our present knowledge in this regard presents a tantalizing picture-we have enough distributional data to feel sure that a knowledge of the complete range of these species would provide excellent material for zoogeographic conclusions, but the data at hand is only sufficient for preliminary speculation. It is hoped that the records in this paper will help to summarize a few of the data that are available, and to stimulate interest in their increase. Unless otherwise mentioned, types described in this paper are deposited in the collection of the Illinois Natural History Survey. The disposition of other type material is indicated by the following abbreviations: