118 University of California Publications. [Entomology 



the end of B are attached can not be compared closely with 

 the basal attachment of the radiating veins in other Orthop- 

 tera. The real basal structures are found on areas A' and B'. 

 The correct interpretation of the parts of this wing is probably 

 that suggested by Scudder, who compares the folding with 

 that described by Saussure in the Blattidfe. This suggestion 

 has never been followed out, though the subject of the homol- 

 ogy of the veins has been discussed by both Brongniart and 

 Redtenbacher. 



According to this theory, the added apical areas, which 

 remain in Blattid?e much smaller than the rest of the wing, 

 become in this insect the major part, everything beyond C and 

 C being comparable with these areas. The increase in size 

 occurs in the posterior of the two areas, the anterior being 

 represented by the area V. The development of an earwig 

 wing from the more complicated conditions found in the Blat- 

 tidse is not much more difficult to understand than the first 

 production of the complex cockroach type. We only need to 

 imagine that the hind apical area, becoming larger, wrinkles 

 up fan-like when it is folded, and that the veins which develop 

 in the membrane adjust themselves so as to facilitate this fold- 

 ing. The lengthening of the membrane in this region would 

 result in the bending back of the tips, with which new modifi- 

 cation the veins would accommodate themselves, and finally 

 the increase of this area would so encroach upon the anal 

 region that it would lose its original fold, or perhaps, rather, 

 merge it with the fold that brings the tip of the wing backward. 

 • This explanation accounts for the difference between the 

 character of the veins in areas A' and B' as compared with the 

 corresponding areas further on, and seems to present no 

 particular difficulty of any kind. 



There are three kinds of veins in the apical region of the 

 wing: One having basal attachments; another, alternating 

 with them, and scarcely more than half as long, without basal 

 attachments; and a third consisting of cross veins. There is a 

 slightly different union between the cross veins and the two 

 kinds of longitudinal veins, indicating a real difference between 

 the longitudinals. The shorter ones have much the appear- 

 ance of independent veins, and the others probably have grown 

 out from the vein bordering the fold, in the same way that the 

 principal veins arose from the base of the wing. It would be 



