« PTERONEPIONITES." 67 



possessed the same number of brandies of the radial sector as in B. priscotincta, 

 its total length would have been 70 mm. — an unusual length. The median vein is 

 the most powerful of the whole series, and occupies a middle diagonal area equal 

 in extent to the combined costal and radial areas. The first branch arises in line 

 with the radial sector, and much nearer the base of the wing than in B. priscotincta, 

 and also lies so much nearer the cubitus that the area separating the two is but 

 half the diameter of the area in the former species. This shortening of the main 

 stem and its movement inwards has been brought about by the division of the 

 second branch into two equal twigs, which pass out to the margin between the 

 first branch and the main stem. The median vein therefore takes a larger share 

 in the wing-structure than in B. priscotincta, and the radial and cubital areas are 

 correspondingly reduced. The cubitus presents no special features. Notwith- 

 standing the shortening up of the area separating it from the median, the area 

 between the cubitus and the anal veins is very large. The cubitus has suffered no 

 displacement by the increased division of the median. The first anal vein is very 

 long, passing well beyond the first third of the wing and dividing just before 

 reaching the wing-margin. The second anal vein is two-thirds the length of the 

 first, and bends inwards more gradually to the margin, giving off two short oblique 

 branches in its basal half. 



" PTERONEPIONITES." 



Many larvae of fossil biattoids have been recorded, but very few of other 

 groups. These larvae may eventually reveal the changes undergone up to the 

 adult stage, and the development of the neuration of the wings. In addition, the 

 occurrence of larvae in deposits is more likely to be indicative of habitat than the 

 presence of adult wings, as the inability of larvae to fly and their lesser power of 

 flotation would ensure inclusion in adjacent deposits. It is therefore necessary 

 that their occurrence, and as much as possible of their structural appearance, be 

 fully recorded. Any attempt to classify them under genera and species would 

 rather retard than accelerate progress, and it seems advisable to record them 

 under some term which will leave no doubt of their larval character. Handlirsch 

 (' Amer. Journ. Sci.' [4], vol. xxxi, p. 375, 11) LI) has already described 

 larval "wing-cases" of a somewhat similar character under the generic name of 

 " Lameereites," and placed them under the order Megasecoptera. 



Had not Handlirsch given a generic value to the name " Lameereites, " it would 

 have been possible to extend the use of his term to all larval wings. Failing this 

 I would suggest the use of the word " Pteroiiepionites " for all larval wings which 

 cannot be referred to a known genus, adding a specific designation when any larval 

 wing presents features of a definitely recognisable character. Handlirsch restricts 

 the name " Lameereites " to the wings of larval Megasecopteridae, but recognises the 



