. The Cambridge natural history. Zoology. 344 NEUROPTERA fragile forms have not been preserved in the rocks, or have not attracted the attention of collectors ; but as some of the palaeozoic Insects were absolutely the largest known—surpassing consider- ably in size any Insects at present existing—it is probable that, even if small forms existed at the remote epoch we are alluding to, the average size of the individual was greater than it is at present. The Megasecopterides of the carboniferous epoch were Insects of large size, with long, narrow wings, a small prothorax, and large meso- and me
. The Cambridge natural history. Zoology. 344 NEUROPTERA fragile forms have not been preserved in the rocks, or have not attracted the attention of collectors ; but as some of the palaeozoic Insects were absolutely the largest known—surpassing consider- ably in size any Insects at present existing—it is probable that, even if small forms existed at the remote epoch we are alluding to, the average size of the individual was greater than it is at present. The Megasecopterides of the carboniferous epoch were Insects of large size, with long, narrow wings, a small prothorax, and large meso- and meta-thorax, these two segments being equal in size; the abdomen was elongate and moderately voluminous, and was terminated by a pair of very elongate, slender filaments like those of the may-flies. The family includes several genera and species found at Commentry. One of these forms, Gory- daloides srAidderi, is of great interest, as it is believed by Brong- niart that the imago possessed tracheal gills situated on the sides of the abdomen, analogous with those that exist at present in the immature condition of certain Ephemeridae. They are of interest in connexion with the gills found at the present time in the imagos of Pteronarcys (see ^. 401). Although these fossils are of such enormous antiquity, the tracheae can, M. Brongniart says, be still perceived in these processes. The Platypterides include also a considerable number of Insects of large size, with four large equal wings, frequently spotted or variegate. Some of these Insects were provided with expansions or lobes on the sides of the prothorax (Fig. 213); these are looked on as analogous to the ex- pansions of meso- and meta- thorax, which are supposed by some writers to have been the rudiments from which wings were developed. These prothoracic wing-rudiments, if. Fig. 213.—Lithomantis carionaria. Car- boniferous strata of Commentry, France. (After Brongniart.) such they be, are said to have a system of nervures
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