THE PALEONTOLOGICAL DATA 



101 



sector, with or without accessory veins, which results in the vein resembling 

 the typical radius in form. This is well-illustrated by Dictyoneura libellu- 

 loides (Fig. 95), which is a simple example of this type; and by Hadromuria 



Fig. 96. — Hadroneura bohemica (After Handlirsch) . 



boJiemica (Fig. 96), in which the type is complicated by the addition of 

 several accessory veins, although the front branch remains isolated. In 

 these and in other figures, I have labeled this isolated front branch as vein 

 Ml +2; my reason for doing this will be given later. 



Let us now determine the type of branching of media in the oldest insect 

 remains that have been found up to the present time, that is in those of the 

 Lower Upper Carboniferous. The exact locality in which each of these 

 fossils was found has been indicated in the foregoing discussion of the radial 

 sector, and need not be given here. The figvires are repeated, however, for 

 convenience of reference. 



In Metropator piissillus (Fig. 97) the media is five-branched, and the 

 branching is dichotomous. It differs from the h\'pothetical type by the 

 presence of an extra branch 

 on vein M4. This is corre- 

 lated with a similar condi- 

 tion in other veins. The 

 radial sector is also typical 

 with an accessory branch on 

 vein R2 and one on vein R3. 

 Vein Cui also bears a short 

 accessory branch. Only a 

 small part of the anal area 



Fig- 97- — Metropator pnssillus (After Handlirsch). 



is preserved, but there is enough to show that the first anal vein was 

 branched. 



Of about the same age as the fossil just described are two from Indiana 

 and one from Alabama. The best preserved of these three is Paolta 

 vehista (Fig. 98). In this wing media has many branches; but the branch- 

 ing is dichotomous. It is easy to recognize the tj'pical form of media with 

 the addition of several accessory branches. 



