S. H. SCUDDER ON THE EARLY TYPES OF INSECTS. 



19 



perfectly reproducing the customary and yet unique features of the Phasmida of to-day. 1 

 The family had not previously been knoAvn earlier than the Tertiaries. 



We may glean still another fact from the scanty data the rocks afford us concerning the 

 early types of insects. All the Hemiptera of the palaeozoic rocks belong to the Hom- 

 opterous division of the suborder ; indicating, what is generally conceded, that this division 

 is lower than the Heteroptera, which first appeared in the Jura. 2 Now one conspicuous 

 difference between these two divisions is found in the structure of the base of the front 

 wings, which is coriaceous in the Heteroptera and membranous in the Homoptera ; show- 

 ing that differentiation of the front and hind wings is, as we should suppose it might be, a 

 later development, the homogeneous condition preceding it. Among Orthoptera, none of 

 the families, unless it be the walking-sticks, have more densely coriaceous fore-wings than 

 the earwigs and the cockroaches. The earwigs first appeared in the Oolite ; and while 

 cockroaches were abundant from the earliest times, it is not, with one exception, until we 

 reach the Lias that we find species with close approximation and multiplication of the veins 

 of the front wings, giving them a coriaceous appearance. This exception, Ledrophora 

 Girardi, 3 in which the veins are nearly obsolete, occurs in the Trias ; and it is the earliest 

 indication of any differentiation of the front and hind wings in cockroaches ; for all the 

 palaeozoic species had tegmina which were as distinctly veined as the wings, and could not, 

 in any sense, be called coriaceous. 4 The same distinctness of the veins is apparent in all 

 the other palaeozoic Orthoptera ; so that, excepting the two species of Carboniferous Coleo- 

 ptera and Protophasma (which do not appear to differ in this respect from living types), 

 we may say that the wings of palaeozoic insects were homogeneous. 



Inasmuch as we know the earliest insects principally from the remains of their wings, it 

 is interesting to note in them a further striking fact. If we should formulate the charac- 



1 Since the above was written, I have received from M. 

 Brongniart his final memoir on Protophasma (Note stir un 

 nouveau genre d' Orthoptere fossile de la faniille des Phas- 

 miens — Ann. Sci. Nat., [6] vn, Art. 4), by which it ap- 

 pears that the wings must be excepted from the statement 

 given above ; for they differ remarkably from the wings of 

 living Phasmida, and resemble extraordinarily the wings of 

 Palaeodictyoptera, and especially those of Dictyoneura. 

 They could not have been folded longitudinally to the de- 

 gree that the wings of Phasmida are now plaited, for the 

 anal area embraces less than one-third of the wings, and 

 the interspaces between the veins of that part of the wing 

 which lies above the anal area, are not straight but curved ; 

 in the number and arrangement of the veins in this upper 

 part of the wing we have an almost exact counterpart of the 

 wings of Dictyoneura; the same, to a less extent, may be 

 said of the wings of the Fulgorina described by Golden- 

 berg. This type of wing structure was therefore a very 

 common one among palaeozoic insects, and accounts for 

 Brongniart's suggestion, hardly to be received, that these 

 Fulgorina should be considered Neuropterous ; indeed the 

 neuration of the wings of the numerous carboniferous 

 Blattarise does not lack a somewhat close adherence lo the 

 same type, and we may yet succeed in establishing an un- 

 usual degree of homogeneity in the wing structure of all or 

 nearly all palaeozoic insects. 



2 Perhaps a similar statement may be made even of the 

 few Coleoptera known. For, if we accept LeConte's prim- 

 ary division of Coleoptera into normal and rhyncoph- 

 orous, the former the higher, and look upon the Troxites 

 of Goldenberg, as I strongly incline to do, as a curculionid, 

 — the only indication of the higher normal Coleoptera in the 

 palaeozoic rocks will be the borings brought to notice by 

 Geinitz, which were evidently made by a longicorn, a 

 family of normal Coleoptera ranking rather low in the 

 series. 



3 Heer. Ueber die fossilen Kakerlaken. < Viertel- 

 jahrschr. naturf. Gesellsch. Zurich, ix : 297, pi., fig. 5. 8°. 

 Zurich, 1864. 



4 Exception should perhaps be made to the very remark- 

 able cockroach described by Goldenberg (Faun. Sar. foss., 

 I : 17, pi. 2, fig. 14, 14a), under the name of Blattinainsignis; 

 this insect has a slender, perhaps cylindrical, abdomen with 

 tegmina and wings which appear to be equally leathery and 

 in which nearly all trace of veins are lost. Here, however, 

 all the wings appear to be alike in form, consistency and 

 structure ; and Goldenberg has given us only a meagre ac- 

 count of it, which is the more unfortunate, since it is second 

 in interest only to Eugereon and Protophasma. 



