Vol. 1.] 



Wood wortli. — Wing Veins of Insects. 



129 



become connected with the principal veins, and they appear 

 often as recurrent branches. Beyond the fold the veins are 

 broad, flat, and solid. There are also two independents 

 between the first and second posteriors. These are often more 

 or less fused and are generally connected to the adjacent veins 

 by long cross veins. The second posterior is generally double 

 and branching, with one or two cross veins. Behind the sec- 

 ond there is at least one other posterior vein. 



Redtenbacher, and Comstock and Needham ('98-99, p. 561/) 

 have overlooked the independents in front of the first poste- 

 rior, and have locat- 

 ed vein VII (=Cu) 

 on the independ- 

 ents behind this 

 vein. In this they 

 are certainly wrong. 

 None of them have 

 advanced any con- 

 vincing argument in 

 support of their iden- 

 tification. Atracto- 

 cerus is an aberrant 

 rather than a primi- 

 tive member of this 

 order, but there is 

 nothing in its venation that would lead to the conclusion that 

 the veins have the homologies assigned to them by these 

 authors, and the data in reference to tracheation are, to say 

 the least, conflicting. The evident character and position of 

 the veins certainly conform to the other interpretation. 



FIG. 70. Venation and folding of Staphylinus ciii- 

 noptaroux. Dotted lines indicate folds; biacli areas 

 are those reversed in folding. 



NEOPTERA. 



The Diptera, Hymenoptera, and Lepidoptera, which consti- 

 tute this group, have been supposed by many investigators to 

 form a single natural super-order, but the transition stages 

 connecting these orders are difficult to conceive of without 

 going back to their neuropterous ancestors. They are the only 

 large groups, unless it be the Coleoptera, that were entirely 

 absent in the Paleozoic era. In all other cases there were 

 species present that possessed enough of the characteristics 

 of existing orders to make their recognition quite easy. 



9— V 



