Vol. 1.] 



Woodworth. — Wing Veins of Insects. 



103 



that time, and there is but little reason to think that all the 

 other insects grouped under this head have a similar structure. 

 One should not give too much attention, therefore, to the classi- 

 fication, if he desires to make a just interpretation of the vena- 

 tion. Whole series of families whose differentiation was not 

 associated with flight can, for the purposes of the study of 

 venation, be considered as a unit. The same dictum will apply 

 to the higher groups as well as to these lower forms. 



XENONEURID.K. 



The insect which is the type and sole member of this family 

 is one of the smallest of the Paleozoic fossils, and possesses 

 the simplest venation. It seems to 

 be distinct enough from everything 

 else to deserve a separate place. 

 There is nothing so unusual in the 

 venation, however, as would cause 

 surprise if further discoveries should 

 connect it with the common Neurop- 

 tera. As will be seen by the accompanying sketch (Fig. 38) 

 the venation is simply a reduced form of the primitive type. 



:^ 



FIG. ;iS. Remains of the wing 

 of Xenoneuridic, after Scudder. 



HEMKRISTINA. 



This group seems to be another case of a very composite 

 family brought together by the character of the venation. 



The character upon which it is 

 founded is the relatively greater 

 size of the first group of inde- 

 pendents, as compared with 

 those that follow. This differ- 

 be clearly seen by 

 comparing the accompanying 

 diagram (Fig. 39) with that of 

 the Paleopterina (Fig. 37). Members of the latter family, as 

 well as of the one now under consideration, have been identified 

 by Brauer ('86) as Sialids. 



GERARINA. 



The character upon which this group is founded, the direct 

 attachment of a number of independents to the primary, seems 

 more likely to prove of value in making a natural classification, 



FIG. 39. Diagram of the venation of ^'^'^'^^ Will 

 the Hemeristina, omitting oross veins 

 and most variable independents. 



