CLASSIFICATION 175 



is, like all others, a quite artificial one, while it is of little 

 value, owing to the development of so few Insects being hitherto 

 fully ascertained. 



Brauer's Classification. 



Professor Brauer has recently proposed l to adopt 1 7 Orders 

 or chief groups of Insects, arranging them as follows : 



I. APTERYGOGENEA (with one order). 



1. Synaptera ( = Aptera of our system). 



II. PTERYGOGENEA ( = all the other Insects of our arrangement). 



2. Dermaptera ( = Orthoptera, Fam. Forficulidae in our arrangement). 



3. Ephemeridae ( = a division of Neuroptera in our arrangement). 



4. Odonata, ( = a division of Neuroptera in our arrangement). 



5. Plecoptera ( = Neuroptera, Fam. Perlidae in our arrangement). 



6. Orthoptera ( = our Orthoptera Forficulidae and + Embiidae). 



1. Oorrodentia ( = the families Termitidae, Psocidae, and Mallophaga, of 

 our Neuroptera). 



8. Thysanoptera (as with us). 



9. Bhynchota ( = Hemiptera with us). 



1 0. Neuroptera ( = the families Hemerobiidai and Sialidce of our Neuroptera). 



11. Panorpatae ( = the family Panorpidae of our Neuroptera). 



12. Trichoptera ( = the division Trichoptera of. Neuroptera}. 



13. Lepidoptera ( = as with us). 



1 4. Diptera ( = our Diptera Aphaniptera). 



1 5. Siphonaptera ( = Aphaniptera, a division of Diptera with us). 



16. Coleoptera ( = Coleoptera). 



17. Hymenoptera (as with us). 



The chief characters on which Brauer bases his system are : 

 (1) The existence or absence of wings. (2) The condition of the 

 mouth, and whether it undergoes radical changes in the ontogeny, 

 arriving thus at the categories Menognatha, Metagnatha, and 

 Menorhyncha, as we have mentioned on p. 161. (3) The meta- 

 morphosis; the grouping adopted being Ametabola, Hemimetabola, 

 Metabola. (4) The number of the Malpighian tubules ; 

 Oligonephria, Polynephria. (5) The nature of the wings, the 

 relative proportions of the thoracic segments, and some other 

 characters. 



Brauer's treatise is accompanied by a valuable and in many 

 respects very sagacious consideration of the generalised char- 

 acters of the Insecta ; as a classification based partly on general- 

 isations and partly on structures, it is, so far as the present 

 1 "Syst. Zool. Studien." S.J5. Ak. Wien, xci. 1885, Abth. I. p. 374. 



