CHAPTER IV 



THE PALEONTOLOGICAL DATA BEARING ON THE DEVELOPMENT AND 

 THE SPECIALIZATION OF THE WINGS OF INSECTS 



(a) EARLY VIEWS AS TO THE PALEONTOLOGICAL EVIDENCE 



In the development of the uniform terminology of the wing-veins almost 

 no use was made of paleontological data. In fact the conclusions drawn 

 from the study of fossil insects by the older writers tended to retard rather 

 than to advance this development. 



It was commonly assumed at the time Redtenbacher wrote his "Ver- 

 gleichende Studien iiber das Fliigelgeader der Insecten" that the wings of 

 May -flies resemble closely the wings of the primitive winged insect; and 

 there are frequent references in the literature of that period to the supposed 

 fact that the older insects had a "richer" wing- venation than that of most 

 of the recent insects. Thus Redtenbacher (1. c. p. 153) makes the following 

 statement : 



"The geologically older Orthoptera and Neuroptera show a much richer venation 

 than the Coleoptera, Lepidoptera, Hymenoptera, and Diptera; likewise among the 

 Rhyncota the oldest forms, the Cicadas and the Fulgoridae, possess much more numerous 

 veins than the Hemiptera. There is apparently, then, no doubt that the oldest insect 

 forms were provided, to a certain extent, with a superfluity of veins, and that, in the 

 course of development, all the superflous veins disappeared by reduction, and in this 

 way a simple system of venation was brought about." 



The accuracy of this conclusion was first seriously questioned by Corn- 

 stock and Needham.* At the time we wrote our "The Wings of Insects" 



;~-x 



Fig- 73- — Xenoneura anliqiiorum (After Scudder). 



the fossils described by Mr. Sct:ddcr from St. Johns, New Brunswick, were 

 supposed to be from Devonian rocks, and consequently to be the oldest 

 well-preserv'ed insect remains. Regarding these we wrote as follows: 



"Of the Devonian insects, the remains of several are known. Those 

 that are best preserved are Homothetus Jossilis (Fig. 74), Xenoneura anti- 

 quorum (Fig. 73), and Platephemera antiqua (Fig. 75). (The figures given 



''The American Naturalist, Vol. 33, p. 125. 



(85) 



