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Larvae of the North American
Caddisfly Genera (Trichoptera)
Second edition
Caddisflies are one of the most diverse groups of organisms living in freshwater habitats,
and their larvae are involved in energy transfer at several levels within these communities.
Caddisfly larvae are also remarkable because of the exquisite food-catching nets and por
table cases they construct with silk and selected pieces of plant and rock materials.
This book is the most comprehensive existing reference on the aquatic larval stages of
the 149 Nearctic genera of Trichoptera, comprising more than 1400 species in North
America. The book is invaluable for freshwater biologists and ecologists in identifying
caddisflies in the communities they study, for students of aquatic biology as a guide to the
diverse fauna of freshwater habitats, and for systematic entomologists as an atlas of the
larval morphology of Trichoptera.
In the General Section, the biology of caddisfly larvae is considered from an evolution
ary point of view. Morphological terms are discussed and illustrated and a classification of
the Nearctic genera is given. Techniques are outlined for collecting and preserving larval
specimens and for associating larval with adult stages. The Systematic Section begins with
a key to larvae of the 26 families of North American Trichoptera. Each chapter in this sec
tion is devoted to a particular family, providing a summary of biological features and a key
to genera, followed by a two-page outline for each genus with illustrations facing text.
This outline provides information on general distribution, number of species, distinctive
morphological features, and biological data including construction behaviour.
An important feature of the book is the habitus illustrations of larvae and cases of a
selected species in each genus, along with illustrations of details of significant morpholog
ical structures. Each generic type is thus presented as a recognizable whole organism
adapted in elegant ways to particular niches of freshwater communities.
This revised edition includes advances in knowledge on the classification and biology
of Trichoptera up to 1993 - an interval of 17 years since the first edition. An additional
eight families and thirteen genera are included for the first time. Through reorganization
of the families into three suborders, a biological context has been established for the sys
tematic section.
Glenn B. Wiggins is Curator Emeritus in the Department of Entomology, Royal Ontario
Museum, and Professor Emeritus in the Department of Zoology, University of Toronto.
The first edition was selected by Choice, a publication of the Association of College and
Research Libraries, as one of the outstanding academic books of 1978.
GLENN B. WIGGINS
Larvae o f the North American
Caddisfly Genera (Trichoptera)
2nd edition
UNIVERSITY OF TORONTO PRESS
Toronto Buffalo London
© University of Toronto Press Incorporated 1996
Toronto Buffalo London
Printed in Canada
ISBN 0-8020-2723-7 (cloth)
Printed on acid-free paper
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Canadian Cataloguing in Publication Data
Wiggins, Glenn B.
Larvae of the North American caddisfly
genera (Trichoptera)
2nd ed. I
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Includes index.
ISBN 0-8020-2723-7
1. Caddisflies - Canada. 2. Caddisflies -
United States. 3. Insects - Larvae.
4. Caddisflies - Identification. 5. Caddisflies -
Canada - Identification. 6. Caddisflies -
United States - Identification. I. Title
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QL517.1.AIW531996 595.7'45'0971 C95-932174-8
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University of Toronto Press acknowledges the financial assistance to its publishing
program of the Canada Council and the Ontario Arts Council.
This book is dedicated to Professor Herbert H. Ross
I consider it as of the utmost importance fully to recognise that the amount of life in any
country, & still more that the number of modified descendants from a common parent, will
in chief part depend on the amount of diversification which they have undergone, so as
best to fill as many & as widely different places as possible in the great scheme of nature.
Charles Darwin
Charles Darwin's Natural Selection (p. 234) ed. R.C. Stauffer 1975
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Contents
Preface to the First Edition ix Associating larval stages 37
Preserving, storing, and shipping
Preface to the Second Edition xii specimens 38
Studying specimens 40
GENERAL SECTION
SYSTEMATIC SECTION
Introduction 3
Objectives 4
Geographic limits 5 Key to larvae of North American
Organization and methods 5 families of Trichoptera 43
Use of keys 7
Suborder Spicipalpia 49
Classification 8 1 Family Glossosomatidae 50
2 Family Hydrobiosidae 67
Biological considerations 14 3 Family Hydroptilidae 71
Ancestral habitat 14 4 Family Rhyacophilidae 110
Habitat diversity 14
Respiration 15 Suborder Annulipalpia 117
Feeding 19 5 Family Dipseudopsidae 118
Construction behaviour 21 6 Family Ecnomidae 123
Life cycles 22 7 Family Hydropsychidae 126
8 Family Philopotamidae 150
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Morphology 26 9 Family Polycentropodidae 159
Head 26 10 Family Psychomyiidae 174
Thorax 28 11 Family Xiphocentronidae 185
Abdomen 30
Suborder Integripalpia 189
Techniques 35 12 Family Apataniidae 190
Collecting 35 13 Family Beraeidae 203
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Contents
14 Family Brachycentridae 206 23 Family Phryganeidae 374
15 Family Calamoceratidae 218 24 Family Rossianidae 399
16 Family Goeridae 226 25 Family Sericostomatidae 404
17 Family Helicopsychidae 237 26 Family Uenoidae 413
18 Family Lepidostomatidae 241
19 Family Leptoceridae 249 Literature cited 427
20 Family Limnephilidae 268
21 Family Molannidae 352 Taxonomic index 453
22 Family Odontoceridae 359
VlIl
Preface to the First Edition
This is a reference work to the identity, structure, and biology of larvae of the North Amer
ican caddisfly genera. More precisely perhaps, it is a stage in the evolution of such a refer
ence, for a definitive work even at the generic level is still well beyond the information
now available. The book is the result of a project I began some years ago to increase
knowledge about larval Trichoptera in North America. Systematic collections on which it
is based were brought together in the course of more than 150,000 miles of travel in field
expeditions through many parts of Canada and the United States, especially in the western
mountains where the fauna is highly diverse yet little explored. Associations between lar
val and adult stages were established for some 350 species, approximately 30% of the
1200 or so species of Trichoptera now known in the two countries; over 200 of these were
established for the first time.
Although the information made available is still far short of enabling one to produce
keys for the identification of North American caddisfly larvae to the species level, it repre
sents a substantial advance at the generic level. Since the genus in the Trichoptera, as in
most groups, represents an ecological as well as a morphological type, it provides a useful
and an incisive base for generalization. To date, 142 Nearctic genera are recognized and
larvae have been identified for all but 6 (4%); diagnostic characters for larvae of 14 genera
are given here for the first time, and from this general project characters for an additional
16 genera were originally published elsewhere. Having gained a better understanding of
the range of larval characters covered by most genera, I have been able to establish more
precise diagnoses for them and consequently have introduced many new characters into
the generic keys. Ultimately, of course, keys for identification of larval Trichoptera to the
species level will provide the most effective aid to workers in freshwater biology, but, in
general, this level of precision is not possible in North America because sufficient basic
data have not yet been assembled.
I am conscious of my good fortune in having the support of several institutions and
agencies in this project. The Royal Ontario Museum has provided the working facilities
for my studies, and the documented collections on which they are based are part of the
research materials of the Department of Entomology. In the early years of my field work,
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Preface to the First Edition
1962-68, when intensive surveys were made in the western United States, financial sup
port was received from the National Science Foundation. Operating grants from the
National Research Council of Canada have supported the project in recent years. Funds
from the Fisheries Research Board of Canada and from the Canadian National Sports
men's Show have also been received. Substantial grants toward the cost of publishing this
book were received from the National Research Council of Canada and the Publications
Fund of the University of Toronto Press. For all of this support I am profoundly grateful.
Figures for the book were prepared by Mr Anker Odum, until recently the scientific
illustrator in our department. They are sufficient evidence of Mr Odum's considerable
ability in this field and of his own fascination with insects; I shall add only that I have
worked closely with him in an attempt to ensure that every drawing conveyed as much
accurate morphological information as possible.
Individual acknowledgment to all of the persons who have contributed in some way to
this project is not possible here, but I am most grateful for the cooperation, generosity, and
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encouragement that I have everywhere received. To Mr Toshio Yamamoto of our depart
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ment lowe special gratitude for his knowledgeable and enthusiastic assistance in field
work and innumerable other aspects of the project. Several others who were members of
our field expeditions have contributed substantially to the growth of the collections on
which the work is based: D. Barr, H.E. Frania, L.H. Kohalmi, B.P. Smith, LM. Smith, and
the late R.S. Scott. Professor Rosemary Mackay of the University of Toronto has been
helpful in resolving ecological matters and problems of many kinds. It is this sense of
community in acquisition and analysis of the collections which underlies use of the pro
noun we throughout.
My professional colleagues have responded generously to requests for specimens,
information, and comment. It is a pleasure to acknowledge this cooperation from N.H.
Anderson, D.G. Denning, O.S. Flint, J.e. Morse, Y.H. Resh, H.H. Ross, F. Schmid, S.D.
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Smith, J.D. Unzicker, and J.B. Wallace.
Students in Aquatic Entomology at the University of Toronto and at the Lake Itasca
Biology Sessions of the University of Minnesota (1970, 1972, and 1974) helped me to
appreciate that keys for identification of insects are too often inconclusive and inade
quately illustrated. In affording me opportunities to test earlier versions of the present
keys, they also helped to confirm my suspicion that when effort is invested in producing
extensively illustrated keys, learning can be'at least easier and is more often exciting.
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Services made available through the Royal Ontario Museum are invaluable in a work
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of this kind, and this book represents supporting contributions of many persons: those
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involved in the entire museum process lead(ng to deposition of adequately documented
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specimens in the research collection, secretaries and photographers in hours of careful
work during preparation of the manuscript;· arid librarians for their efforts to maintain the
reference base essential for research in systematics. I wish also to acknowledge the assis
tance of lC.E. Rioue for translation of important reference works, Sharon Hick for com
piling the literature citations, Zile Zichmanisfqr art work, and Felix Barlocher for analysis
of larval food. In acknowledging these contributions, I extend my appreciation to those
directors and trustees of the Royal Ontario Museum whose support my work has had over
the years of my curatorial appointment. I hope that they will see in this book another
example of the ROM's 'record of nature through countless ages.'
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