718 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxix. 



strongly chitini/ed swelling at the ])ase of the anterior border. The 

 radius is more or less eopiously l)ranched, and only in the most primi- 

 tive forms still shows the typical ancestral separation into radius and 

 sector. The entire radial group is mainly divided into several clus- 

 ters of twigs, or the branches all arise iipparentl}" on the superior side 

 of the principal vein. The media is either separated into 2 main com- 

 pound offshoots, or it forms one vein with branches running otl' )>ack- 

 wai-d, or, finally, one such with the branches ramifying anteriorly; 

 All these modifications are united by transition forms. 



In a majority of cases the culntus sends out its branches sloping to 

 the inner margin; more rarely there is one isolated, widely furcating 

 superior offshoot. The anal area is alwa3's marked otl' by a bow- 

 shaped furrow and contains a number of veins which fuse in the pos- 

 terior margin. 



The intercalary venation is either irregidarly reticulate or it con- 

 sists of very delicate regular cross veins. In the forms whose wings 

 are more tinnly chitinized, we find in place of these cross veins only a 

 more or less irregular leather}^ structure, which further often exhibits 

 distinct cross wrinkles. 



In the primitive forms the body is more slender; in those more 

 highly developed, often greatly expanded. Cerci are well developed, 

 distinctly jointed. Legs more or less slender, often with spines. 

 Antenna? slender. 



PAL^^OBLATTA, ne^A' genus. 



With this name I distinguish a very primitive form, which in many 

 respects shows great similarit}" to certain protoblattoids (H't/ca^nus, 

 Genipovipu.^^ etc.) and which in their venation very strikingl}' resemble 

 the palfeodictyopteran type, so that they could be referred with almost 

 equal right to the protoblattoids as to the blattoids. 



The subcosta reaches somewhat beyond half the length of the wing 

 and sends out about 10 branches. The radius proceeds in a nearly 

 straight course to the tip of the wing and above the end sends off 

 about 10 branchlets to the anterior margin. The radial sector origi- 

 nates in the typical manner above the middle of the wing and forms 1 

 twigs. The media likewise separates a))ove the middle of the wing 

 into 2 equally furcate branches, of which the last end in the inner 

 margin. The cubitus sends 4 oblique branches to the inner margin. 

 The anal area is slender and attains nearly half the length of the wing; 

 it is defined by a gently curved yein and contains several (about .5) in 

 part compound veins which end in the posterior ))order. The inter- 

 calary venation is irregular and occasionally reticulate. The costal 

 margin is strongly curved, and the costal area wide. Wing 2| times 

 as long as broad. Shield of the pronotum comparatively small, 

 almost semicircular in form. Abdomen rather slender. 



