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the pioneer entomology by William Kirby and William Spcnce. "Were a naturalist to announce to the world," they write, "the discovery of an animal which first existed in the Fossil Insects form of a serpent; which then pene- trated into the earth, and weaving a Frank M. Carpenter shroud of pure silk of the finest texture, contracted itself within this covering into a body without external mouth or limbs, and resembling, more than any- Written in the rocks of Colorado, thing else, an Egyptian mummy; and Kansas, Oklahoma, and many other which, lastly after remaining in this places is the story of insects in the ages state without food and without mo- before man appeared on earth. tion . should at the end of that pe- The insects were trapped, caught in riod burst its silken cerements, struggle mud or sticky resin, and thereby left a through its earthly covering and start permanent record—as did dinosaur, into day a winged bird—what think mollusk, and plants—that broadens you would be the sensation excited by our knowledge of their evolution. this strange piece of intelligence ? After About 12,000 species of fossil insects the first doubts of 'its truth were dis- have been described. Countless thou- pelled, what astonishment would suc- sands of specimens have been collected. ceed! Amongst the learned, what sur- Fossil insects are not found in as mises!—what investigations! Even the many deposits or localities as most most torpid would flock to the sight of other invertebrates. Like other organ- such a prodigy." isms, insects are preserved as fossils by a sequence of events that results in EDWIN WAY TEALE is a past presi- their burial in a suitable medium. Im- dent of the New York Entomological mediate burial is necessary to preserve Society and the author of numerous the whole insect ; otherwise the body books on insects, including Grassroot parts soften and fall apart, and only Jungles, The Boys' Book of Insects, the wings remain. The wings decom- Near Horizons, The Golden Throng, pose more slowly and therefore can be and North With the Spring. His hooks preserved under less favorable condi- have appeared in British, Spanish, tions. That is the reason why many French, Swedish, Finnish, and Braille specimens of fossil insects consist of editions. Near Horizons was awarded wings alone. When conditions were the John Burroughs Medal for distin- good for preserving insects, large num- guished nature writing. In ig4g, Mr. bers of fossils usually occur. Teale edited a one-volume omnibus of An example of such abundance is the writings of F abre, entitled The provided by the Tertiary shales at Flo- Insect World of J. Henri Fabre. rissant, Colo., which have yielded up- wards of 60,000 specimens. The shale originated about 40 million years ago in a shallow lake, extending into sev- eral narrow valleys and rimmed by granitic hills. Several neighboring vol- canoes frequently erupted and scat- tered ashes and debris over a wide area. Whatever insects were flying or were being blown over the lake at those .^^ times were forced into the water by the falling ashes and were promptly buried. Stenomema canadense, a common mayfly. Fossil insects have been found at 14 Fossil Insects nearly 150 localities in various parts of and Ural River in the east. The north- the world. About nine-tenths of the ern and western borders are uncertain specimens have been collected at 12 of because those regions are covered by these deposits. The remainder has com.e the ocean. At any rate, the local ac- from less productive rocks. Some of the cumulation of the amber along the latter are important because of their coast of East Prussia is the result of the geological position, however. One of washing out of the flooded forest. In- them is the Commentry shales of cen- sects and other small invertebrates, tral France. These were deposited by which were caught in the resin on the a deep fresh-water lake, which existed tree trunks, arc preserved in great de- during the Upper Carboniferous pe- tail and perfection. At least 150,000 riod some 250 million years ago. About insects have been found in the amber. 1,500 specimicns have been found in The earliest geological record of the the shales. They are well preserved and insects is still uncertain. Fragments of are almost the oldest insects known. small arthropods, which have been re- Another deposit, notable for the covered in a Devonian chert in Scot- abundance of fossils as well as their land, have been determined by some ages, is the Elmo limestone in eastern entomologists as Collembola (spring- Kansas. The rock, fine-grained and tails), but the identity will remain nearly white, w^as deposited by a shal- doubtful until more is known about low fresh-water lake inhabited by them. The oldest unquestionable in- aquatic insects, crustaceans, and small sects have been found in rocks of early king crabs. A collector who carefully Upper Carboniferous age, about 250 breaks the limestone, after it has been million years ago. Only three of these dug up and dried, may get as many as fossils are known—one each from 50 good insects a day. Most of the fos- Czechoslovakia, Germany, and Penn- sils arc strikingly well preserved. Some sylvania—and each consists of a single show even the coloration and minute wing. Whatever else may be inferred hairs on the wings. About 10,000 speci- from the specimens, it is certain that mens so far have been collected there. insects with fully developed wings ex- A similar but more extensive lime- isted then. stone formation was discovered in 1940 Insects are much more abundantly in northeastern Oklahoma. It origi- represented in the later Upper Carbon- nated in a shallow, saline lake, barren iferous rocks than in the earlier ones, of life except for algae and bivalve so that we have at least a working crustaceans (Conchostraca). Most of knowledge of the insect fauna of the the insects preserved there were pre- time. Six orders of insects have been sumably carried to the lake by floods. recognized, all but one of them extinct. The lithographic limestone of Ba- The most interesting was the Palaeo- varia, famous for such fossil vertebrates dictyoptera, which were of medium as the flying reptiles and the earliest size and resembled mayflies. Since birds, is not nearly so important for its some of the Palaeodictyoptera were insects. Several thousand specimicns more generalized than any of the other have been found there, but fev/er than winged insects known, the group as a one-tenth of them are well preserved. whole is usually considered to be the The richest of all deposits is the Bal- ancestral stock from which all other tic amber from Germany. The mate- winged insects have been evolved. As rial is itself the fossil resin from an far as we know, all species of the order extinct pine tree {Pinites succinijera). had a pair of membranous lobes on the The Amber Pine Forest existed for first thoracic segment. The lobes ap- several million years during the early pear to be homologous with the func- Tertiary period, and extended from tional wings of the other two thoracic about the site of Bornholm and Rügen segments and are regarded as indicat- in the south to that of the White Sea ing the steps by which functional wings i6 Yearbook of Agriculture 1952 arose. Unfortunately nothing is known Geological Ages of Existing Orders of about the immature stages of the Pa- Insects laeodictyoptera. The order reached its Na7ne of order Earliest geological record maximum development in the Carbon- CoUcmbola Devonian [?]. iferous period but persisted through Entotrophi Middle Tertiary, Thysanura Jurassic. the Permian period. Odonata Lower Permian. The most spectacular insects of the Ephemeroptera . Lower Permian. Carboniferous and Permian were the Plecoptera Upper Permian. Protodonata. They resembled dragon- Orthoptera Triassic. Orthoptera Upper Garbonif- fíies. Their chewing mouth parts were (Blattidae). erous. powerful, and their legs, like those of Isoptera Lower Tertiary. true dragonflies, were covered with Dermaptera Jurassic. strong spines. They were undoubtedly Embioptera Lower Tertiary. Corrodentia Lower Permian. prcdaceous, catching their victims in Mallophaga [No fossils known.] flight and devouring them w^hile rest- Hemiptera Lower Permian. ing on tree ferns or other ancient Anoplura Quarternary. plants. All of the Protodonata were Thysanoptcra .... Upper Permian. Mccoptera Lower Permian. large and some were veritable giants, Neuroptcra Lower Permian. having a wing expanse of 30 inches and Trichoptera Jurassic. a body length of 15 inches. Specimens Diptera Jurassic. of such large species have been found Siphonaptera Lower Tertiary. Lepidoptera Lower Tertiary. in rocks in France, Kansas, and Okla- Coleóptera Upper Permian. homa. Since birds and other flying Strepsiptera Lower Tertiary. vertebrates did not exist at that time, Hymenoptcra .... Jurassic. these huge insects presumably ruled the air. Their nymphs have not been sects. Although the several extinct found, but they were probably aquatic orders which arose in the Carbonifer- and like those of true dragonflies or ous still existed, several living orders damselflies. besides the roaches were represented. The only living order or group of Along with the giant dragonflies WTTC families of insects known to have ex- minute barklice, only one-eighth of an isted in Carboniferous time is the Blat- inch across the wings. Altogether, the tidae, or cockroaches. Their remains lower Permian insect fauna was very make up a high percentage of insects of diverse—more so, in fact, than any that period, but that is probably due other insect fauna known. There was partly to the favorable conditions pre- about equal representation of the ex- vailing in the Carboniferous swamps tinct orders of the Carboniferous and that produced the deposits.

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