396 EXTERNAL ANATOMY OF INSECTS, 



I have considered it invariably with a strict attention to its 

 relative value ; that is, first, as to its relation to neighbouring 

 parts in the same insect ; secondly, as to its relation to the same 

 part in other insects. I have endeavoured to avoid bringing 

 into notice extravagant or monstrous appearances in particular 

 genera or species, as exemplifications of any proposition, 

 believing that these bear no higher value, in a general system, 

 than a deformed individual does in a species ; that they are 

 not plans of nature, but departures from her plans ; not rules 

 of nature, but exceptions to her rules : for the entomologist 

 cannot but observe, that these strange conformations are not 

 necessary developments of muscle for the support of increased 

 action in organs of locomotion, &c. ; for where the increased 

 use of either pair of locomotive organs is observable, the seg- 

 ment bearing those organs is increased in volume through 

 whole orders, or even classes ; and is never, as far as 1 have 

 yet observed, limited in its increase to a genus or family. I 

 fear, that in thus generalizing, I shall by some be charged 

 with being superficial ; but it is my firm impression, that 

 we have been too prone to insulate facts ; too eager to 

 notice and comment on wonders, which would probably cease 

 to be such were the range of our meditations allowed a wider 

 field. 



On the subject of system it may be thought that I have 

 elsewhere indulged somewhat too freely, — a point which time 

 must settle : I have merely made such allusions to it here as 

 the subject of the present essay renders compulsory ; for 

 instance, in tracing the progressive development of particular 

 parts, I have adhered to the position of the seven classes 

 which I formerly proposed ; and in doing this I furnish the 

 reader with a test by which the worth of any system may be 



prothorax ; mesothorax ; scutellum ; manitrunk ; collar; ring; neck; behind the 

 head ; anterior margin of thorax ; anterior portion of thorax ; anterior part of 

 thorax ; segment of thorax ; first segment of thorax ; anterior segment of thorax ; 

 first portion of the trunk ; first segment of the trunk ; second segment of thorax ; 

 second segment in an insect. Inferior writers have added to this list, as have also 

 the writers above alluded to in other parts of their works. The names now in 

 use in this country alone for this one segment, considered as a whole, are thirty- 

 nine. The fore-wings of insects are called elytra, hemelytra, pseudelytra, tegmina, 

 coriaria, alee, ala: anticce, ala prima, alee primores, alee primaria, al<B anteriores, 

 ^■c. c'^-c, besides English names. 



