ZOOLOGICAL
56
ODONATA (Dragon-Flies). Plate 35, Map v.
These handsome and attractive insects are universally distributed, but attain their greatest variety in the warmer regions of the earth. About 2000 species are known at the present day, and these are arranged in two principal divisions according to the relative size of the fore and hind wings, while about seven smaller groups or sub-families may be recognised. About 300 species occur in Worth America, and just over 100 in Europe. Britain possesses 40 which are truly native, and some of these are fairly familiar objects, attracting attention either by their beautiful and vivid colours, or by their large size and rapid and powerful flight.
ORDER TRICHOPTERA.
TRICHOPTERA (Caddis-Flies). Plate 35, Map v.
The Caddis-flies in their adult state are moth-like insects, usually seen in the neighbourhood of streams and lakes. Their larvae are well known and of much interest, from the wonderful nature of their habitations, which are in the form of more or less cylindrical, and sometimes spiral cases, built of tiny stones, grains of sand, fragments of weed, or other materials. About 1300 species have been described up to the present day, and these are grouped into 13 distinct families. Some 150 occur in Worth America, 500 in Europe, and 150 in Britain, but all these numbers will probably be much augmented when the group receives more attention.
ORDER ORTHOPTERA.
LOCUSTIDiE (Green Grasshoppers, &c.). Plate 35, Map v.
The Locustidse, sometimes called Phasgonuridse, are distinguished from their relatives, the Acrididse, chiefly by the length and delicacy of their antennae, which are composed of a large number (always more than 30) joints. They are of universal distribution, but most abundant in warm countries. In the most recent catalogue the names of about 3200 species are given, and these are distributed among no fewer than 694 genera, and 24 sub-families. Only nine or ten species occur in Britain, and the majority of these are confined to the extreme south of England.
ACRIDIDjE (Locusts). Plate 35, Map vi.
A strange confusion exists between the popular and scientific names of this and the preceding family. Thus, the true Locusts are not Lomstidse, but Acrididx, while the term Grasshopper is equally unsatisfactory. The members of the present family may, however, be conveniently known as “Short-horned Grasshoppers,” in accordance with their most prominent characteristic, namely, their relatively short antennae, consisting of less than 30 joints. Like the Locustidse these insects are universally distributed, but the species are more numerous, over 4250 having been described. For the reception of this multitude of forms, about 840 genera have been founded, arranged in 12 sub-families. Only 11 species are found in Britain, but those of the genera Stenobothrus and Gomphocerus are tolerably common.
PHASMIDiE (Stick and Leaf Insects). Plate 35, Map vi.
The Phasmidse are, in general, the most extraordinary-looking of all insects, resembling twigs, green or withered leaves, or other parts of plants. They are widely spread over the globe, but are more abundant in the tropical portion. About 950 species are known, which are arranged in about 200 genera and 16 sub-families. About a dozen species are found in Worth America, and four or five in Europe, where they are mostly confined to the south. They are entirely absent from the British Isles, and appear to reach their zenith in Australia. One of the most extraordinary species known is Eurycantha horrida, a creature inhabiting Wew Guinea and some of the neighbouring islands.
MANTIDiE (Praying Insects). Plate 35, Map vi.
Like the members of the preceding family, the so-called “ Praying Insects ” are creatures of extraordinary appearance, and many of them closely resemble leaves and even flowers. They are easily recognised by their powerful spined front pair of legs, which are used for seizing their prey. The name “praying insect ”bears allusion to their habit of resting with their front legs held out in a peculiar manner, wdiich is supposed to simulate an attitude of prayer. The distribution of Mantidse is practically the same as that of the Phasmidse. About 830 species have been described, belonging to just over 200 distinct genera, and constituting eight sub-families. Some 20 species occur in Worth America, but only in the southern portion, while in Europe only about a dozen occur, likewise in the south. The best-known European species, Mantis religiosa, is a frequent inhabitant of southern and central France, but no member of the family occurs in Britain.
VERTICAL AND LATITUDINAL DISTRIBUTION.
Plate 36.
This Plate is an adaptation of one prepared by W. Marshall, which forms Wo. 60 of Berghaus’ Physikalischer Atlas (Abteilung YI, Atlas der Tierverbreitung). Wo revision of details has been attempted, but a slightly different arrangement has been made of the groups of animals concerned, merely for the sake of clearness. The distribution of marine life, as shown by Marshall, has been omitted for the same reason, but three insets are given to show the bathymetrical range of a few selected families of Fishes and Molluscs. These are based principally upon information given in the Challenger Reports.
ORDER DIPTERA.
CULICIDÆ (Gnats or Mosquitoes). Plate 35, Map ii.
Since the remarkable discovery was made that certain insects of this family play an important rôle in the dissemination of certain tropical diseases, such as malaria, yellow fever, &c., much attention has been bestowed upon them. From this increased activity, a much better knowledge of their distribution has been obtained, while the number of described species has been augmented to a remarkable degree. At the present day fully 500 species are known, distributed among about 70 genera. They are found in every part of the world, Europe possessing about 50 species and Worth America about 40. In Britain 26 species have been recorded, and some of them are found in all parts of our islands. Anopheles, whose distribution is shown separately on the Map, is a genus comprising about 17 species, at least two of which [A. maculipennis and bifurcatus) are known to be carriers of the parasite which causes malaria. Stegomyia (also shown on the Map) is likewise an important genus. About 20 species are known, one of which (״S', fasciata) is the sole agent in the dissemination of that scourge of the Tropics, yellow fever.
TABANIDÆ (Horse-Flies, Clegs, &c.). Plate 35, Map iii.
This family is composed of about 1600 species, some of which are among the bulkiest of known Diptera or Two-winged Flies. They are found in all parts of the world, and are all more or less addicted to blood-sucking, but this habit is confined to the members of the female sex. About 200 species inhabit the Palsearctic Region, about the same number the Wearctic Region, and about 300 the Ethiopian. Britain possesses 25, which are placed in the five genera Hæmatopota, Therioplectes, Atylotus, Tabanus and Chrysops.
SYRPHIDÆ (Hoverer Flies). Plate 35, Map iii.
The flies of this family are among the most attractive in appearance of all the Diptera, their bodies being often elegantly adorned with bands and spots of yellow, or covered with brightly coloured hair. Their popular name is due to their interesting habit of hovering in the air apparently quite motionless, while if disturbed they dart off with lightning-like rapidity, and after a short time return again to hover hawk-like at the same spot. Fully 2500 species are known, and these are found in every part of the globe. Over 300 occur in Worth America, about 600 in Europe, and 200 in Britain.
GLOSSINA (Tsetse Flies). Plate 35, Map iii.
This genus of flies, belonging to the family Muscidæ, has of recent years sprung into much prominence, owing to the fact that at least one of its species (Glossina palpalis) has been proved to convey the parasite which causes the dreadful African disease known as “sleeping sickness,” while another (G. morsitans) is the carrier of the parasite which produces “ Nagana ” or “ fly-disease,” so destructive to horses, cattle and other domestic animals. Fortunately for the rest of the world this genus is practically confined to tropical Africa. Ten species have been described, but only the two mentioned have been proved to assist in the dissemination of disease.
ORDER HEMIPTERA.
COCCIDÆ (Scale Insects). Plate 35, Map iv.
In this important family about 1500 distinct species have been described. They are of universal distribution, and in some countries are of the greatest importance from the economic point of view, inasmuch as they are probably more destructive to the various fruit and other crops cultivated by man than any other group of insects. Nearly 400 species are found in North America, one of the best-known being the notorious “San José Scale,” which is a most destructive pest in California and other parts of the United States. On the other hand, certain members of this family produce wax and other materials of much use to man. Lac, cochineal, and axin, the latter a substance used externally in medicine, are examples.
ORDER NEUROPTERA.
MYRMELEONTIDÆ (Ant-Lions). Plate 35, Map iv.
About 300 species of Ant-Lions are known at the present day. These range over the greater part of the world, but are more abundant in the warmer regions. Although entirely absent from Britain, yet they occur on the continent of Europe, practically as far north as the Arctic Circle. Some of the forms inhabiting the Ethiopian and other regions are quite handsome insects, with an expansion of wing of four inches or more.
TERMITIDÆ (Termites or White-Ants). Plate 35, Map iv.
These insects are of much interest, both on account of their remarkable nests and also because of the wonderful details which have been ascertained respecting their social life. Their habitations, built of earth, wood, or other material, sometimes reach a height of 15 to 20 feet, and in such cases form conspicuous objects in the landscape. About 350 species have been described, but this number is probably only a small proportion of those which actually exist. From their habit of eating wood they become in some countries exceedingly destructive to furniture and even whole build-ings. These insects are very widely distributed, being mainly found in the warmer regions of the globe. Few species occur in North America or in Europe, while they are quite absent from Britain.