MosLEY : On Classification of British Insects. 5 



task upon entomologists, from time immemorial to say, which is the 

 most natural way of arranging these tiny creatures. 



The first system worthy of note is that invented by Swammerdam, 

 in which he divides insects into four primary groups as follows : — 



1. Insects subject to a change of sidn, but undergoing no change of 

 form (spiders, lice, woodlice, and centipedes). 



2. Hexapod insects subject to metamorphosis, having an active 

 pupa, in which the rudimentary wings and wing-cases are exposed 

 (bugs, dragon-flies, grasshoppers, and mayflies). 



3. Hexapod insects undergoing metamorphosis, in which the pupa 

 state is quiescent, either having the limbs enclosed in distinct cases 

 (beetles, bees, wasps, &c., and part of the Neuroptera and Diptera), or 

 covered with an entire case (butterflies, moths). 



4. Hexapod insects undergoing metamorphosis, the pupa state 

 having neither motion or wings, but enclosed in an ovate case (most 

 Diptera and other insects). 



This system which is based upon the form or condition of the pupa^ 

 is imperfect in splitting up closely allied groups. For instance, the 

 Neuroptera and Diptera are each split and placed in two divisions. 



Leaving the older and coming to more modern times we find another 

 system of classification of winged insects propounded by Ed. Newman, 

 and based upon the characters of the pupa, which is very similar to one 

 propounded by Lamarck. Like Swammerdam, Newman makes four 

 primary divisions, viz : — 



1. Amorpha^ in which the pupa has ^neither mouth nor organs of 

 locomotion and bears no resemblance to the perfect insect (Lepidoptera 

 and Diptera. 



2. NecromorpJia^ in which the pupa has both mouth and organs of 

 locomotion, but enveloped in several cases, and incapable of use 

 (Hymenoptera, Coleoptera). 



3. Isomorpha.^ in which the mouth and limbs are present and used 

 (Orthoptera, Hemiptera). 



4. Anisomorpha, in which all the before-mentioned characters are 

 present, and some independent ones (Neuroptera). 



This system, though presenting certain degrees of correctness, yet 

 brings together insects of little afiinity, and at the same time 

 separates others which are nearly allied, like the Neuroptera and 

 Trichoptera. It is likewise subject to many exceptions; we find 

 necromorphous pupae among the lepidoptera — the burnets, for 

 instance. Some dipterous pupae are locomotive ; the Coleoptera, and 

 especially the Neuroptera, present many striking exceptions. 



