682 ARTHROPODA SUB-KINGDOM VII 
Several Diplopods are found in the Tertiary, especially in amber. Examples: Julus, 
Linn. (Fig. 1440); Craspedosoma, Leach; Euzonus, Menge ; 
Polyxenus, Latr.;  Phryssonotus, Scudder (Lophonotus, 
Menge). 
Susp-PuyLtum C. Insecta (Hewapoda). Insects.4 
Tracheate Arthropods with body at maturity consisting 
of three divisions—head, thorax, and abdomen; supplied 
with a pair of antennae on the head, three pairs of legs, and 
usually two pairs of wings on the thorax. The latter is 

Fia. 1440. 
Julus antiquus, Heyden. Mio- 2 
cene ; Rott, near Bonn, Germany. composed of three, and the abdomen of nine or ten segments. 
Copy, "/1- Development usually through metamorphic stages. 
Fossil Insects can be referred, usually without difficulty, to the existing orders of 
Aptera, Orthoptera, Neuroptera, Hemiptera, Coleoptera, Diptera, Lepidoptera, and 
Hymenoptera. The Palaeozoic forms, however, show a less marked differentiation in 
the structure of their wings and are more closely related to each other than their 
successors of the corresponding orders. Scudder, on this account, unites these primitive 
precursors by placing them in a special group (Palaeodictyoptera), and compares its 
representatives, under the names of Orthopteroidea, Neuropteroidea, Hemipteroidea, and 
Coleopteroidea, with the typical Orthoptera, Neuroptera, etc., of later date. 
The researches of C. Brongniart ? regarding the rich Palaeozoic fauna of Commentry, 
although they lead to the conclusion that strangely differentiated forms occurred in 
the different groups even in the Carboniferous, show even more conclusively than 
before that this differentiation had little depth, and that it is only through their 
presumable descendants that we have any claim to a wide separation of the original 
Palaeozoic forms. The neuration of the wings, though diversified, had yet a far 
greater homogeneity than is found now, or than existed during Mesozoic time. The 
fore wings of whatever type were as diaphanous as the hind, and could never (as in most 
of their descendants) properly be called tegmina. The wings of the Protodonata (Fig. 
1260) of Brongniart had indeed a superficial resemblance to living Odonata in shape, 
reticulation, and sweep of the veins ; but in fundamental neuration they were altogether 
different, and they wholly lacked any sign of those characteristic features of the 
Odonata, termed the nodus, triangle, and pterostigma, which appear fully developed in 
the Mesozoic species. Nor should it be forgotten how highly probable it is that the 
Lepidopteran, Dipteran, and Hymenopteran phyla had their origin in types already 
recognised in the Palaeozoic. In a text-book, however, and perhaps in any general 
treatise, it may be best to bring the Orthopteroidea, Neuropteroidea, etc., in direct 
connection with the Orthoptera, Neuroptera, etc., as indicative of the precise phylogeny 
of the latter groups. 
Order 1. APTHRA. 
Wingless insects with hairy or scaly body covering ; with rudimentary masticating 
mouth parts and setiform anal filaments, which may serve as a springing apparatus, at 
the end of the ten-segmented abdomen. Development without metamorphosis. 
1 [The most complete guides to the literature of fossil Arachnids, Myriopods, and Insects are to 
be found in the writings of Professor Samuel’H. Scudder, of Cambridge, Mass., who has revised the 
translation of these chapters for the present work—without, however, having altered their system- 
atic arrangement. One should consult especially his collection of papers in two volumes, entitled 
Fossil Insects of North America (New York, 1890) ; Budletin of the United States Geological Survey, 
Nos. 31, 69, 71, 93, 101, 124; Vol. XIII. of the Annual Reports ; and XXI. of the Survey Mono- 
graphs (Washington, 1886-95) ; also his discussion of the above-named groups in Zittel’s Handbuch 
der Palaeontologie, Vol. 11. (Munich and Leipsic, 1885).—TRans. ] 
2 See his important work: Recherches pour servir a Uhistoire des insectes fossiles des temps 
primaires, 2 vols., St. Etienne, 1893, 
