into two Classes. cxcv 



the vertebrated animals, invariably seek to include all animals, 

 however aberrant, in one or other of the primary divisions : we 

 occasionally see much ingenuity exhibited in settling the ques- 

 tion to which division an animal belongs ; for instance, Orni- 

 thorhynchus, Lepidosiren, Pterodactylus, Deinotherium, Ich- 

 thyosaurus, have all afforded scope for argumentative writing in 

 this way: entomologists would unhesitatingly have ranked these 

 as primary groups of vertebrated animals, equivalent to mam- 

 mals, birds, reptiles and fishes ; but it seems to me that the ge- 

 neral zoologists are right in considering to which established 

 group such abnormal forms can be referred, rather than in cre- 

 ating new groups purposely to receive them. Applying the 

 same reasoning to insects, I think we ought to inquire to what 

 established entomological group an aberrant species or genus 

 belongs, rather than to create a new group purposely for its re- 

 ception. Assuming then that Thrips is referrible to an esta- 

 blished group, we have next to consider to what group it is 

 referrible. 



Secondly. — The metamorphosis of Thrips is totally different from 

 that of Lepidoptera, Diptera, Hymenoptera, Coleoptera, and 

 Stegoptera ; it agrees tolerably well with that of Orthoptera and 

 Hemiptera, and is positively identical with what we know of 

 that of the Perlina, Psocina, and Termetina among the Neuro- 

 ptera. 



Thirdly. — The structure of the mouth absolutely forbids its associ- 

 ation with the Hemiptera or Orthoptera, but differs no more 

 from that of Neuroptera, than those of the divisions of Neuro- 

 ptera do among themselves : for instance, than the Perlina do 

 from the Agrionina, the Psocina from the Perlina, the Epheme- 

 rina from all the rest : the mandibles, considered so anomalous, 

 are almost exactly similar to those of Corydalis cornuta in the 

 Stegoptera, which no one has ever attempted to separate from 

 its congeners. 



Fourthly. — The perfect similarity of the fore and hind wings in 

 Thrips is characteristic of Neuroptera, and especially of the 

 Agrionina and Termitina, and is totally at variance with what 

 obtains in all other classes. 



On these grounds I have no hesitation in expressing my decided 

 conviction that the Thripsina form an integral part and a primary sec- 

 tion of the Neuroptera. 



