23.4 Baker: Malayan Jassoidea 347 



development of a general system adapted to include the immense 

 number of forms now in collections, or toward a general and 

 much-needed revision of the genera of the world. We are still 

 trying to use, to include all of the jassoid insects of the world, 

 the very ancient and artificial system originally proposed for 

 a few species formerly known in Europe. If the ocelli were 

 on the disk of the crown, the insect was a tettigoniellid, if on 

 the margin a jassid, and if on the face a bythoscopid; quite 

 disregardf ul of the fact that the ocelli are on the vertex, morpho- 

 logically speaking, in all of these groups. The utter impos- 

 sibility of classifying these insects on an artificial one-character 

 basis is very evident in every work that is published on new 

 and little-known faunae. There is little wonder that Distant 

 could not place Chudania or Pythamus in any of the older fami- 

 lies! Genera of the closest relationships have been placed in 

 remote parts of the ancient "system," and genera of no funda- 

 mental relationship are thrown together. Superficial characters 

 cannot be used for general grouping. General outlines of head 

 and pronotum, head thick or thin, etc., are characters widely 

 variable even within the same genus. 



In the Nirvaniidaa, among insects of the closest relationship, 

 strongly similar in color pattern and body form, the ocelli may 

 be on the anterior surface of the crown (sometimes far from 

 the margin), on the border between crown and face, or on the 

 upper surface of the face below the border of the crown. Vena- 

 tion can only be used with many reservations. Many of the 

 cross veins are very variable in position and often may be 

 present or absent in the same species. To separate two genera 

 because one has "four apical cells" and another "five apical cells," 

 when it is well known that the subcostal apical cell is a very 

 uncertain feature, is fruitless unless coordinate diagnostic 

 characters can be found. A tegmen of Signoretia benguetensis 

 is figured here (Plate 1, fig. 7) in which one of the usually 

 constant cross veins, that at apex of the first subapical cell, is 

 obsolete, leaving only a stump on one side. In Pythamus this 

 cross vein is regularly absent. The normal forking of the 

 main veins is of importance, but one branch of the fork may be 

 distinct or indistinguishable in the same genus or even species, 

 as in some of the Nirvaniidae. Also, the method of examination 

 has made many generic descriptions misleading. In one of 

 the genera of this group described as having venation obsolete, 

 when the tegmen is mounted on a slide and viewed by strong 

 transmitted light the venation is perfectly distinct. Another, 



