Directions for Collecting and Preserving Insects

Charles V. Riley

Directions for Collecting and Preserving Insects

Published by Good Press, 2022

[email protected]

EAN 4064066171940

Table of Contents

INTRODUCTORY.

MANUAL OF INSTRUCTIONS FOR COLLECTING AND PRESERVING INSECTS.

CHARACTERISTICS OF INSECTS.

SCOPE AND IMPORTANCE OF ENTOMOLOGY.

CLASSIFICATION OF HEXAPODS.

COLLECTING.

COLLECTING APPARATUS.

COLLECTING HYMENOPTERA.

COLLECTING COLEOPTERA.

COLLECTING LEPIDOPTERA.

COLLECTING HEMIPTERA.

COLLECTING DIPTERA.

COLLECTING ORTHOPTERA.

COLLECTING NEUROPTERA.

KILLING AND PRESERVING INSECTS.

ENTOMOTAXY.

CARE OF PINNED AND MOUNTED SPECIMENS.

PRESERVATION OF ALCOHOLIC SPECIMENS.

LABELING SPECIMENS.

INSECT BOXES AND CABINETS.

ARRANGEMENT OF INSECTS IN THE CABINET.

MUSEUM PESTS, MOLD, ETC.

MOLD.

VERDIGRISING AND GREASING.

THE REARING OF INSECTS.

DIRECTIONS FOR TRANSMITTING INSECTS.

INSTRUCTIONS FOR COLLECTING AND PRESERVING ARACHNIDS AND MYRIAPODS.

DIRECTIONS FOR COLLECTING SPIDERS.

COLLECTING OTHER ARACHNIDS: MITES, TICKS, SCORPIONS, ETC.

COLLECTING MYRIAPODA.

TEXT BOOKS—ENTOMOLOGICAL WORKS.

COMPREHENSIVE WORKS MOST USEFUL FOR THE STUDY OF NORTH AMERICAN INSECTS.

GENERAL WORKS ON CLASSIFICATION.

AMERICAN PERIODICALS.

FOREIGN PERIODICALS.

LIST OF MORE USEFUL WORKS ON ECONOMIC ENTOMOLOGY.

ENTOMOLOGICAL WORKS PUBLISHED BY THE UNITED STATES ENTOMOLOGICAL COMMISSION AND BY THE UNITED STATES DEPARTMENT OF AGRICULTURE.

HOW TO OBTAIN ENTOMOLOGICAL BOOKS AND PAMPHLETS.

INTRODUCTORY.

Table of Contents

There is a constant demand, especially from correspondents of the Museum and also of the Department of Agriculture, for information as to how to collect, preserve, and mount insects. There is also great need of some simple directions on a great many other points connected with the proper packing of insects for transmission through the mails or otherwise; labeling; methods of rearing; boxes and cabinets; text-books, etc. Interest in the subject of entomology has, in fact, made rapid growth in the last few years, and now that nearly every State has an official entomologist connected with its State Agricultural Experiment Station, the number of persons interested in the subject may be expected to increase largely in the near future. I have hitherto made use of the Smithsonian Miscellaneous Collections, No.261, which is a pamphlet on collecting and preserving insects prepared by Dr.A.S.Packard. This is out of print, and I have been requested by Prof. Goode to prepare for Bulletin 39, U.S.N.M., something that would cover the whole ground and give the more essential information needed for collectors and students of insect life. I have deemed it unnecessary to go too much into detail, but have studied not to omit anything essential. Customs and methods vary in different countries and with different individuals, but the recommendations contained in the following pages are based upon my own experience and that of my assistants and many acquaintances, and embrace the methods which the large majority of American entomologists have found most satisfactory.

Much of the matter is repeated bodily from the directions for collecting and preserving insects published in my Fifth Report on the Insects of Missouri (1872) and quotations not otherwise credited are from that Report. The illustrations, also, when not otherwise credited or not originally made for this paper, are from my previous writings. Some are taken from Dr.Packard's pamphlet, already mentioned; others, with the permission of Assistant Secretary Willits, from the publications of the Department of Agriculture, while a number have been especially made for the occasion, either from photographs, or from drawings by Miss L.Sullivan or Dr.Geo.Marx or Mr.C.L.Marlatt. When enlarged, the natural size is indicated in hair-line. In the preparation of the pamphlet I have had the assistance of Mr.E.A.Schwarz, and more particularly of Mr.C.L.Marlatt, to both of whom I desire here to express my obligations.

C. V. R.

Pl. 1.—Illustration of Biologic Series.

MANUAL OF INSTRUCTIONS FOR COLLECTING AND PRESERVING INSECTS.

Table of Contents

By

C. V. Riley

,

Honorary Curator of the Department of Insects, U. S. National Museum.

CHARACTERISTICS OF INSECTS.

Table of Contents

The term insect comes from the Latin insectum, and signifies cut into. It expresses one of the prime characteristics of this class of animals, namely, that of segmentation. This feature of having the body divided into rings or segments by transverse incisions is possessed by other large groups of animals, and was considered of sufficient importance by Cuvier to lead him, in his system of classification, to group with Insects, under the general term Articulata, Worms, Crustacea, Spiders, and Myriapods. Worms differ from the other four groups in having no articulated appendages, and in having a soft body-wall or integument instead of a dense chitinous covering, and are separated as a special class Vermes. The other four groups of segmented animals possess in common the feature of jointed appendages and a covering of chitinous plates, and are brought together under the term Arthropoda. The division of the body into a series of segments by transverse incisions, characteristic of these animals and these only, justifies the use of Cuvier's old name, Articulates, as this segmented feature represents a definite relationship and a natural division—as much so as the vertebral column in Vertebrates. The Cuvierian name should be retained as a coördinate of Vertebrates, Molluscs, etc., and the terms Vermes and Arthropods may be conveniently used to designate the two natural divisions of the Articulates.

The term insect has been employed by authors in two different senses—one to apply to the tracheated animals or those that breathe through a system of air tubes (tracheæ), comprising Spiders, Myriapods, and insects proper or Hexapods,[1] and the other in its restricted sense as applied to the Hexapods only. To avoid confusion, the latter signification only should be used, and it will be thus used in this article.

We see, then, that insects share, in common with many other animals, the jointed or articulated structure. Wherein, then, do they differ? Briefly, in having the body divided into thirteen joints and a subjoint, including the head as a joint, and in the adult having six true, jointed legs, and usually, though not always, wings. The five classes of Articulates differ from each other in the number of legs they possess in the adult form, as follows: Hexapoda, 6 legs; Arachnida, 8 legs; Crustacea, 10–14 legs; Myriapoda, more than 14 legs; Vermes, none. This system holds for the adult form only, because some mites (Arachnida) when young have only 6 legs, and many true insects in the larva state either have no legs at all, or have additional abdominal legs which are not jointed, but membranous, and are lost in the perfect or adult state. These are called false or prolegs.

It will serve to make these instructions clear if I at once explain that the life of an insect is marked by four distinct states, viz., the egg, the larva, the pupa, and the imago, and that the last three words will constantly recur. We have no English equivalent for the words larva and pupa, for while some authors have written them with the terminal e, so as to get the English plural, yet larves and pupes so shock the ear that the terms have not been (and deserve not to be) generally adopted.

We have seen that an insect in the final state has six true legs. Yet even here many species depart from the rule, as there are many in which the perfect insect, especially in the female sex, is apodous or without legs, just as there are also other cases where they are without wings. Sometimes the legs seem to be reduced in number by the partial or total atrophy of one or the other pair, but in all these exceptional cases there is no difficulty in realizing that we have to deal with a true insect, because of the other characters pertaining to the class, some of which it will be well to allude to.

Insects are further characterized by having usually three distinct divisions of the body, viz.: head, thorax, and abdomen, and by undergoing certain metamorphoses or transformations. Now, while a number of other animals outside of the insect world go through similar transformations, those in the Crustacea being equally remarkable, yet, from the ease with which they are observed and the completeness of the transformations in most insects, the metamorphoses of this class have, from time immemorial, excited the greatest curiosity.

Footnote:

[1] From the Greek εξαπους, having 6 feet.

SCOPE AND IMPORTANCE OF ENTOMOLOGY.

Table of Contents

But few words are necessary to indicate the importance of entomology, especially to the farming community; for while insects play a most important part in the economy of nature and furnish us some valuable products and otherwise do us a great deal of indirect good, yet they are chiefly known by the annoyances they cause and by the great injury they do to our crops and domestic animals. Hence some knowledge of insects and how to study them becomes important, almost necessary, to every farmer.

The scope of the science may best be indicated by a statement of the number of species existing, as compared with other animals. The omnipresence of insects is known and felt by all; yet few have any accurate idea of the actual numbers existing, so that some figures will not prove uninteresting in this connection. Taking the lists of described species, and the estimates of specialists in the different orders, it is safe to say that about thirty thousand species have already been described from North America, while the number of species already described or to be described in the Biologia Centrali-Americana, i.e., for Central America, foot up just about the same number, Lord Walsingham having estimated them at 30,114 in his address as president of the London Entomological Society two years ago, neither the Orthoptera nor the Neuroptera being included in this estimate. By way of contrast the number of mammals, birds, and reptiles to be described from the same region, is interesting. It foots up 1,937, as follows:

Mammals, 180; birds, 1,600; reptiles, 157.

If we endeavor to get some estimate of the number of insects that occur in the whole world, the most satisfactory estimates will be found in the address just alluded to, and in that of Dr.David Sharp before the same society. Linnæus knew nearly 3,000 species, of which more than 2,000 were European and over 800 exotic. The estimate of Dr.John Day, in 1853, of the number of species on the globe, was 250,000. Dr.Sharp's estimate thirty years later was between 500,000 and 1,000,000. Sharp's and Walsingham's estimates in 1889 reached nearly 2,000,000, and the average number of insects annually described since the publication of the Zoölogical Record, deducting 8 per cent for synonyms, is 6,500 species. I think the estimate of 2,000,000 species in the world is extremely low, and if we take into consideration the fact that species have been best worked up in the more temperate portions of the globe, and that in the more tropical portions a vast number of species still remain to be characterized and named, and if we take further into consideration the fact that many portions of the globe are yet unexplored, entomologically, that even in the best worked up regions by far the larger portion of the Micro-Hymenoptera and Micro-Diptera remain absolutely undescribed in our collections, and have been but very partially collected, it will be safe to estimate that not one-fifth of the species extant have yet been characterized or enumerated. In this view of the case the species in our collections, whether described or undescribed, do not represent perhaps more than one-fifth of the whole. In other words, to say that there are 10,000,000 species of insects in the world, would be, in my judgment, a moderate estimate.

CLASSIFICATION OF HEXAPODS.

Table of Contents

Seven orders of insects were originally recognized by Linnæus, namely, Neuroptera, Diptera, Hemiptera, Lepidoptera, Coleoptera, Hymenoptera, and Aptera. This classification was based on the organs of flight only, and while in the main resulting in natural divisions which still furnish the basis of more modern classifications, was faulty in several particulars. For instance, the Aptera, which included all wingless insects, was soon found to be a very unnatural assemblage and its components were distributed among the other orders. The establishment of the order Orthoptera by Olivier to include a large and well-defined group of insects associated with the Hemiptera by Linnæus, restored the original seven orders, and this classification has, in the main, been followed by entomologists up to the present time.

Fig.

1.—Pyramid showing the nature of the mouth, and relative rank of the Orders, and the affinities of the Suborders of Insects.

All insects are, in a broad way, referable to one or the other of these seven primary orders by the structure of the wings and the character of the mouth-parts in the imago, and by the nature of their transformations.

Some of these orders are connected by aberrant and osculant families or groups, which have by other authors been variously ranked as independent orders, but which, following Westwood substantially, I have considered, for convenience, as suborders. (See Fifth Report, Insects of Missouri, etc., 1872.)

In the article just cited, I made use of the accompanying diagram in the form of a pyramid (Fig.1), which gives a graphic representation of the distinguishing characters and the relative rank as usually accepted, of the orders and suborders.

Full discussion of the different classifications is unnecessary in this connection. Authors have differed in the past and will differ in the future as to what constitutes a natural system, and it would require many pages to give even a brief survey of the various schemes that have been proposed. As I have elsewhere said, We must remember that classifications are but a means to an end—appliances to facilitate our thought and study—and that, to use Spencer's words, ‘we cannot, by any logical dichotomies, actually express relations which in nature graduate into each other insensibly.’

The most philosophical, perhaps, of the more modern systems of classification is that of Friedrich Brauer, who has carefully studied the subject, and has given us an arrangement consisting of sixteen orders. This has many merits and has been adopted, with slight modifications, by Packard in his Entomology for Beginners, and by Hyatt and Arms in their recent and valuable text-book Insecta. Comstock, in his Introduction to Entomology strongly recommends Brauer's classification, but for reasons of simplicity and convenience adheres to a modification of the old classification of Westwood.

For purposes of comparison the classification by Hyatt and Arms, which is substantially that of Brauer, may be introduced.

In linear arrangement it is as follows:

The relationship of these orders cannot be indicated in a linear arrangement, and is admirably shown by Hyatt and Arms by means of diagrams which I reproduce (Figs. 2, 3.)

Fig.

2.—Scheme illustrating origin and relationship of Orders. (After Hyatt.)

The relation of these sixteen orders to the older, septenary scheme is shown by the following arrangement:

Fig.

3.—Cross section of Fig.2.

It will be seen that the changes are not so great as would at first appear. The three more important orders, namely, the Hymenoptera, Coleoptera, and Lepidoptera, remain substantially the same in all classifications, and so with the three orders next in importance—the Hemiptera, Diptera, and Orthoptera. All that has been done with these three has been to rank as separate orders what by former authors were preferably considered as either families or suborders. The principal change is in the Neuroptera, of which no less than eight orders have been made. This is not to be wondered at, because the order, as formerly construed, was conceded to be that which represents the lowest forms and more synthetic types of insects, and as such necessarily contained forms which it is difficult to classify definitely.

In the discussion of the characteristics, habits, number of species, and importance of the several groups, I follow, with such changes as the advances in the science of entomology have made necessary, the arrangement shown in Fig.1.

"Order HYMENOPTERA υμην, a membrane; πτερον, wing). Clear or Membrane-winged Flies: Bees, Wasps, Ants, Saw-flies, etc. Characterized by having four membranous wings with comparatively few veins, the hind part smallest. The transformations are complete: i.e., the larva bears no resemblance to the perfect insect.

Fig.

4.—Bold-faced Hornet,

Vespa maculata.

(After Sanborn).

"Some of the insects of this order are highly specialized, and their mouth-parts are fitted both for biting and sucking, and in this respect they connect the mandibulate and haustellate insects. The common Honey-bee has this complex structure of the mouth, and if the editors of our agricultural papers would bear the fact in mind, we should have less of the never-ending discussion as to whether bees are capable of injuring fruit at first hand. The lower lip (labium) is modified into a long tongue, sheathed by the lower jaws (maxillæ), and they can sip, or, more properly speaking, lap up nectar; while the upper jaws (mandibulæ), though not generally used for purposes of manducation, are fitted for biting and cutting. The Hymenoptera are terrestrial, there existing only a very few degraded, swimming forms.

"This order is very naturally divided into two sections—the

Aculeata

and

Terebrantia

. The aculeate Hymenoptera, or Stingers, comprise all the families in which the abdomen in the female is armed with a sting connected with a poison reservoir, and may be considered the typical form of the order, including all the social and fossorial species.

The insects of this section must be considered essentially beneficial to man, notwithstanding the occasional sting of a bee or wasp, the boring of a carpenter bee, or the importunities of the omnipresent ant. Not only do they furnish us with honey and wax, but they play so important a part in the destruction of insects injurious to vegetation that they may be looked upon as God-appointed guards over the