Classifying and Naming Insects

Classification. There are about a million kinds of described animals in the world, and their study calls for some plan of dividing them into groups. Zoologists classify animals chiefly on the basis of structure: those with certain structures in common are placed in one group and those with other structures are put in other groups. These groups are divided and subdivided. The result is a system of categories, each with certain structural features in common, and a name.

The animal kingdom is divided into a number of major groups called phyla (singular, phylum); each phylum is divided into« classes, each class into orders, each order into families, each family into genera (singular, genus), and each genus into species. In many larger groups there are additional categories, such as subclasses, suborders, superfamilies, subfamilies, and tribes. The species is the basic category; it is a kind of animal. That is, it consists of individuals fundamentally similar in structure which interbreed to produce offspring but do not ordinarily interbreed with other groups. Sometimes species are divided into subspecies. Subspecies are generally geographic races that differ from one another only slightly and are capable of interbreeding.

The arrangement of animals into these categories is arbitrary: it is the opinion of the specialist that determines the limits of a category. Although specialists do not always agree on the limits of some categories, differences of opinion mostly are minor. This system is an indispensable tool in the study of animals. Anyone studying animals must be familiar with it.

Nomenclature. Animals have 2 types of names — scientific and common. Scientific names are the names used by scientists; they are used throughout the world, and every animal or group has one. Common names are vernacular names. They are less precise than scientific names, and many animals lack them. Some common names are used for more than 1 species or group, and a given animal or group may have several common names.

Scientific Nomenclature. The scientific naming of animals follows certain rules, only a few of which can be mentioned here. Scientific names are Latinized. They may be derived from various languages or from the names of people and places, but most are from Latin or Greek and refer to characteristics of the animal or group named. Names of groups above genus are single words in the nominative plural; names of genera are single words in the nominative singular; names of species are 2 words — the name of the genus plus a specific name; and names of subspecies are 3 words — the name of the species (2 words) plus a subspecific name. Specific and subspecific names may be adjectives or participles (in which case they must agree in gender with the genus name) or nouns in the nominative or genitive.

Names of genera, species, and subspecies are written in italics and are usually followed by the name of a person (the author). If the author name follows a species name it indicates the person who proposed the specific name; if it follows a subspecies name it indicates the person who proposed the subspecific name; if it is in parentheses it means that the author's species or subspecies was originally placed in a genus other than the present one. For example:

Musca domestica Linn. — the House Fly. Linnaeus (abbreviated "Linn." in this Field Guide) first described the House Fly and gave it the specific name domestica and placed it in the genus Musca.

Automeris io (Fabricius) — the Io Moth. Fabricius first described this moth and gave it the specific name io, and placed it in a genus other than Automeris.

Diabrotica undecimpunctata howardi Barber — the Spotted Cucumber Beetle. Barber proposed the name howardi and placed it in Diabrotica. There is no way of knowing from this name whether Barber originally described howardi as a subspecies of undecimpunctata, or as a subspecies of another species of Diabrotica, or as a species of Diabrotica.

Whenever a new group (from subspecies to superfamily) is described, the describer is supposed to designate a type. This type provides a reference if a question arises as to what the group includes, and type genera provide the basis of the name of certain higher categories. The type of categories from tribe to super-family is a genus, the type of a genus is a species, and the type of a species or subspecies is a specimen.

Names of some categories have standard endings: -oidea for superfamily, -idae for family, -inae for subfamily, and -ini for tribe. The names are formed by adding the ending to the root of the type genus name. If 1 of these groups is divided into 2 or more subgroups, the subgroup containing the group's type genus will have the same name as the group except for the ending. An illustration: Colletes is the type genus of the family Colletidae (plasterer and yellow-faced bees); this family is divided into 2 subfamilies, the Colletinae (plasterer bees; with Colletes) and the Hylaeinae (yellow-faced bees; named for Hylaeus, the genus designated as the type of this subfamily).

This same principle applies when a species is divided into 2 or more subspecies — the subspecific name of one of the subspecies (the one containing the type of the species) will be the same as the specific name of the species. For example, the dragonfly Tetra-goneuria cynosura (Say) is divided into 2 subspecies, Tetragoneuria cynosura cynosura (Say) and Tetragoneuria cynosura simulans Muttkowski. T. c. cynosura contains the type of T. cynosura and another specimen was designated as the type of T. c. simulans.

A given animal (or group) may be described by different people and thus may have more than 1 name. The first name proposed in such cases (provided the author followed certain rules) is the correct one and the other names become synonyms. It is not always easy to determine which of 2 or more names for an animal is the correct one: different names may be used by authorities who do not agree on which name has priority.

It sometimes happens that a person describing a new genus will use for it a name previously used for another genus. When this is discovered the later genus must be renamed, since the rules state that no 2 genera of animals may have the same name. Similarly, no 2 species or subspecies in the same genus may have the same specific or subspecific name. These rules relating to homonyms (cases of the same name being used for different groups) apply only within a particular category group, and they except the case mentioned above of 1 subspecies having the same specific as subspecific name. The category groups are: phylum through order, super-family through subgenus, and species through subspecies. A name used in 1 of these 3 category groups can be used in another without violating the rules. For example, a specific or subspecific name may be the same as the name of a genus, or the same name may be used for both a genus and an order.

As our knowledge of animals increases it often becomes necessary to change scientific names. A group may be subdivided or combined with another group; a name widely used may become a synonym because of the discovery of an older name; or a group may be renamed because of the discovery of an earlier use of its name for another group. Problems encountered in scientific nomenclature are sometimes solved differently by taxonomists. For these reasons, the classification and nomenclature used by authorities may not always be the same. We follow in this book the opinions of most present-day entomologists. Other names and groupings most often encountered are included in the Index.

Common Names. Common names of insects mainly apply to groups rather than to individual species. The few species having common names are generally of some economic importance or are particularly striking in appearance. The name "beetle," for instance, refers to all the Coleoptera, of which there are some 290,000 world species (about 28,600 in the U.S.); the name "leaf beetle" refers to all the Chrysomelidae (about 25,000 world species, nearly 1400 in the U.S.); the name "tortoise beetle" refers to all the Cassidinae, a subfamily of the Chrysomelidae (about 3000 world species and about 24 in the U.S.) ; the name "Argus Tortoise

Beetle" refers to the single species Chelymorpha cassidea (Fabri-cius), which is of economic importance as a pest of sweet potato and other plants.

Most 1-word common names used for insects (beetle, bug, fly, termite, caddisfly, and others) refer to entire orders. Some (damsel-fly, grasshopper, lacewing, and others) refer to suborders or groups of families. Only a few (ants, Formicidae; cockroaches, Blattidae; and others) refer to families. Most common names of families — where the family has a common name — consist of 2 or more words, the last being the name of the larger group and the other(s) descriptive (robber flies, Asilidae; leaf beetles, Chrysomelidae; metallic wood-boring beetles, Buprestidae; and others).

The majority of the comrfion names used in this book are in rather wide use; some are used by relatively few people, and a small number are used here for the first time. Many entomologists prefer scientific to common names because they are more precise and are widely used (at least among entomologists), and are sometimes easier to remember. An adjectival form of a group's scientific name is often used as a common name — a member of the order Orthoptera could be called an "orthopteran," or a member of the family Libellulidae could be called a "libellulid." If a family has no common name (and sometimes even when it does), it is standard practice to use the adjectival form of the family name as a common name. In a few cases (mantids, Mantidae; syrphid flies, Syrphidae; etc.) such names are widely used as common names.

"Fly" and "bug" are a part of the common names of many different insects. The "fly" of the name is written as a separate word if the insect is in the order Diptera (horse fly, robber fly, black fly), and together with the descriptive word if the insect is in another order (butterfly, dragonfly, scorpionfly). The "bug" of the name is written as a separate word if the insect is in the order Hemiptera (stink bug, bed bug, leaf bug), and together with the descriptive word if the insect is in another order (mealybug, lightningbug, ladybug).

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