Steve Marshall is a professor of entomology at the University of Guelph, where he developed a major insect collection and carries out research on insect systematics and biodiversity. He has discovered hundreds of new species, several new genera and even two new subfamilies.

Preface

This book is based on material originally gathered in support of a third-year entomology course -- "The Natural History of Insects" -- that I started teaching at University of Guelph in 1982. The text is based on the lecture notes for that course, the picture keys are based on the course manual and the photographs are part of a collection that was initiated to provide color to my lectures in several entomology courses over the past 20 years.

The text sections in this book provide an introduction to insect diversity and natural history, with basic information about all major insect families. The photos and captions provide a visual overview of the diversity of each family with discussions of common or especially interesting genera and species. Picture keys are provided to the orders and common families of most orders. The emphasis is on northeastern North America, loosely interpreted as anything east of the Mississippi River and north of the state of Georgia.

Insect identification

Although the focus of this book is on the common families of northeastern North American insects, the keys and photos should be useful for identifying orders and most families anywhere in the world. If you are trying to identify an insect to order, start with the illustrated keys (pages 615-666). When you think you have a match, turn to the appropriate section of the book and look over the full spectrum of photos for that order.

If you know the order and want to identify your insect to the family level you can either jump right to the photos and captions, or start with the illustrated keys. The illustrated keys may not take you right to the family level, but they will guide you to the correct part of the book to look for further information. The photos and captions themselves should serve as a practical field guide to the family or subfamily level for common insects from anywhere in North America, and will serve for positive identification of some eastern insects at the genus or species level.

Almost all the photographs are of northeastern species, although a few interesting groups that do not occur in the east (honey ants, pollen wasps) were slipped in for interest, and a few groups are illustrated with photos from outside North America, as noted. The great majority of the photographs were taken in Ontario, Canada (mostly the Bruce Peninsula or southern Ontario), but a few are from Mountain Lake Biological Station, Virginia (where I teach a field entomology course), and elsewhere in the eastern United States.

The illustrated family keys are designed to be as user-friendly as possible, with an emphasis on characteristics visible to the naked eye or easily discernable with a handheld magnifying glass. Most keys represent a compromise between ease of use and comprehensiveness. The keys in this book lean towards ease of use and should be treated as shortcuts rather than definitive roadmaps. The keys to families in the larger orders (Diptera, Hymenoptera, Coleoptera) are designed to aid in the identification of typical members of commonly encountered families, and the odd rarity or exception will not key out. Comprehensive keys to the families of these orders are listed in the references, but most require experience, patience and a good microscope to use. For example, the key to families of beetles in American Beetles (Arnett et al., 2002) is 185 complex couplets long; the key to families of flies in the Manual of North American Diptera (McAlpine et al., 1981) is 152 couplets long. Those keys will work for almost all North American beetles and flies; the simplified keys in this book will probably work for over 95 percent, including almost all routinely encountered taxa. I think it is a good compromise, but it is a compromise, and the serious student will want to check problematic identifications using more technical literature.

The "id" and "idae" of entomological jargon

This book is organized around insect orders and families. Names given to orders (big groups, like beetles and flies) do not have standard endings, but orders are divided into families, and the names of families always end in "-idae." Insect families are routinely mentioned by informally contracting the family name to end with "-id." Ground beetles, for example, are formally called the family Carabidae, but are informally referred to as "carabids." Sometimes it is useful to talk about a number of related families together, in which case we talk about superfamilies and the names always end in "-oidea." Some families, especially large families like the leaf beetles (Chrysomelidae), are usefully divided into subgroups called subfamilies (subfamily names end in "-inae").

The scientific name of a species always has two parts, the genus (always capitalized and in italics) and species (always in italics, never capitalized). For example, the Monarch Butterfly (Danaus plexippus) is a nymphalid butterfly in the family Nymphalidae and the subfamily Danainae. In scientific papers (but not in this book) the name of a species is usually followed by the name of the person who first described and named it (in parentheses if it was first described in another genus). The Monarch, then, would appear as Danaus plexippus (L.), with L. serving as a short form for its "discoverer" Linnaeus.

Taxonomic hierarchy and corresponding suffix
Superfamily: -oidea
Family (formal): -idae
Family (informal): -id
Subfamily: -inae

Many insect species, especially large or economically important species, have common names like the Monarch, but most do not. Where widely used common names exist they are included here. Common names are normally capitalized. Family names appear in bold face when they first appear in the text.

Classifications are in constant flux as we discover more about the relationships between groups of organisms, and the names used in this book may be different from those you are already familiar with. I have taken a conservative approach to higher classification, using the family concepts in current usage unless there are compelling reasons to accept a recent change. Significant changes are indicated in the text and captions, and generally follow a recent checklist, catalogue or monograph in the Selected References section at the back of this book.

An Overview of Six-legged Life

We live in a world of insects. They are our continual and closest neighbors, so much a part of day-to-day life that most of us hardly take notice of them unless they are particularly loud or obnoxious, or they stand accused of robbery or assault. It is easy to forget that human beings form a tiny two-legged minority in an overwhelmingly six-legged world -- a world where a bit of knowledge about our dominant neighbors can unlock the door to a surprisingly diverse local environment. The key to seeing and understanding insect diversity is knowledge of the common orders and families of insects. Armed with that knowledge, a sizeable proportion of the multitude of walking, crawling and flying creatures you share your daily life with will become familiar neighbors, replete with predictable habits.

Insects are influential and interesting creatures well worth getting to know. It is self-evident that you can hardly step outdoors without exposure to a usually ignored infinity of insect types, but surprisingly few people are aware that these ubiquitous animals make up the staggering majority of all living things. Most named species of living things, including close to eighty percent of the approximately one and a half million named animal species, are insects. These numbers would be all the more impressive if they took into account the millions of insect species still awaiting discovery and formal naming. We can only guess that the total number of insect species is somewhere between five and ten million, and we have only the crudest idea of how many individual insects