SOOMYLACRIS DEANENSIS. 129 



The costal margin is strongly convex basally, becoming almost straight over 

 the middle of the wing, in this respect differing from 8. stocki, which is increasingly 

 convex in the middle of the wing a fact noted by Scudder. The inner margin is 

 more nearly straight, and the wing narrows as the apex is reached, the maximum 

 width being across the anal area. 



The subcosta is made up of three main branches, the first forking into two equal 

 twigs, the second forking twice into three twigs, and the third forking three times 

 into four twigs. The subcostal area is very wide basally, and terminates in an 

 acuminate angle beyond the junction of the first and second thirds of the wing. 



The radius is a powerful vein dividing low down into two main branches, the 

 outer breaking up into four twigs by a trifid forking, while the inner branch forks 

 into two, and each of these into two again, the two twigs of the inner secondary 

 fork each dividing into two. The radius thus ends on the broken edge of the wing 

 in ten twigs. 



rtJ& 



FIG. 40.-SoomyZoms deanensis (Scudder) ; diagram of venation of right tegmen (the diagram reversed), 

 twice natural size.-Coal Measures ; Foxe's Bridge, Forest of Dean, Glos. U.S. National Museum, 

 Washington (Lacoe Coll., no. H. 2132 b; Nat. Mus. no. 38090). 



The median vein forks into two main branches at about the end of the proximal 

 third of the wing. The outer branch divides into two equal twigs, the inner 

 forking again further out. The inner branch forks once only on that portion of 

 the wing which is now preserved, although Scudder has figured it as breaking up 

 into six ultimate twigs by repeated forking of the innermost of the two branches 

 now seen. Scudder shows twelve twigs of the median ending on the inner half of 

 the wing-apex, while the actual specimen now shows only five. Scudder is wrong 

 in showing a twig coming off inwardly from the first main division of the median, 

 and dying out in the wing-membrane. The appearance is due to a slight furrow 

 on the impression. This furrow can be traced across the branches of the adjoining 



cub it us. 



The cubitus, like the median, is sigmoidally curved, and gives off five inward 

 branches, and ends upon the distal end of the inner margin in a small fork, 

 second and third branches of the cubitus fork twice, and end on the : 

 three twigs each. 



Unlike the rest of the wing, which is flatly convex, the anal area i 

 rounded, and must have projected somewhat above the general surface. 

 17 



