682 ARTHKOPODA SUB-KINGDOM vn 



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). 



SUB-PHYLUM C. INSECTA (Hexapoda). Insects. 1 



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 



cene ; Rott, near Bonn, Germany, composed of three, and the abdomen of nine or ten segments. 



Copy, 1/1. 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 2 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 frhe 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. APTERA. 



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) ; Bulletin 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 ZitteVs Handbuch 

 der Palaeontologie, Vol. II. (Munich and Leipsic, 1885). TRANS.] 



2 See his important work : Recherches pour servir a Vhistoire des insectes fossiles des temps 

 primaires, 2 vols., St. Etienne, 1893. 





