126 



Scudder(1886),Brongniart (1894) and Handlirsch(1903,'06, '10). 

 Zittel-Broili (1915) agrees with the latter in the main points. 



The number of fossil insects has now become so considerable, 

 that the existence of a palaeo-entomology can no longer be denied. 

 The principal lines of the genealogical tree can already be drawn. 



Handlirsch (1903, p. 720 sqq.) directs attention to the fact, 

 that originally the abdomen consists of 11 segments and a telson, 

 the 11th segment bearing a pair of cerci. 



In the Palaeozoic era there are only Ametabola ; all the different 

 Metabola appear at about the same time, namely in the Permian 

 formation. 



In the Palaeozoicum the relatives of the Polynephria are found, 

 in Perm and Trias the Oligonephria appear. From the fact of 

 their synchronistic appearance it follows, that perhaps a poly- 

 phyletic origin of the higher orders may be assumed, which orders 

 therefore appeared as parallel lines. In the Perm the branch of 

 the Neti rapt eroi (lea and that of the Coleopteroidea are already 

 separated from that of the Panorpoidea. To the latter belong the 

 Phrt/f/dHoideUj Panorpata, Lejndoptera, Sucto7'ia and Diptera. This 

 classification differs entirely from that of Lameere. 



Handlirsch adduces against this writer (1900, p. 174): 



1°. The reduction of the cross-veins. Very often the recent 

 holometabolic Nearoptera and Sialidae still show a more original 

 vein-course than the carbonic Megaseco])tera (the primitive group 

 of the Panorpoidea)^ besides the reduction of the veins is a 

 common feature in lleteromctabola. 



2°. The habit of carrying the wings in a horizontal position 

 is only found in Heterometabola, these alone have well-developed 

 cerci; the Mega^ecopterous-\a,v\diQ d\m had wing-sheaths like that, 

 and therefore were probably heterometabolic too. 



3°. The Lepidoptera are originally phytophagous and they only 

 become secondarily endophagous. In this case organisms would have 

 been driven in a progressive direction by the influence of parasitism 

 according to Lameere, whereas as a rule they degenerate . by it. 



4°. If we adhere to a monophyletic origin of all Holometabola, 



