EXTERNAL ANATOMY OF INSECTS. 401 



12. (W. X) Paratelum. 



13. (Y. ^.) Telum, bearing the organs of reproduction,"' or some- 



times being confined to those organs" or weapons 

 of defence." 



I will now state what has previously been done in this way. 



Linnaeus divided an insect into head, thorax, and abdomen; 

 a division, the propriety of which being universally acknow- 

 ledged, has been employed by all writers •" from his day to the 

 present ; yet a division diametrically at variance with nature : 

 in fact, the limits of the parts were ideal ; or, in other words, 

 it has always been perfectly optional with a describer to limit 

 the thorax to the second segment, or include in it any number, 

 not exceeding the four following segments ; and in this ento- 

 mological writers have not been influenced by any philosophi- 

 cal rules, but have been guided solely by the relative size of 

 the segments : the same has been the case with the abdomen, 

 which may comprise seven, eight, nine, ten, or eleven of the 

 segments ; and it so happens, that the segments, which are 

 thus either thorax or abdomen, bear the wings ; so that the 

 wings are either thoracical or abdominal appendages, as an 

 entomologist pleases. In a beetle, they are generally consi- 

 dered abdominal ; in a bee, thoracical. Chabrier and Andouin, 

 in their excellent observations on the anatomy of insects, have 

 applied to the wing-bearing segments the names which I have 

 retained, and have treated the subject with great skill; the 

 former renouncing the term thorax as applicable to a series of 

 parts, but unaccountably leaving the reader to determine 

 whether he shall consider the four wings as arising from one 

 segment or two ; for he expressly terms the site of these organs 

 *' segment allfere" and yet divides it into mesoihorax and 

 metathorax. Andouin, though a most accomplished writer 

 and able reasoner, retrogrades a step, by again uniting the 

 prothorax with Chabrier's "segment alifere," under the ori- 

 ginal name thorax. Kirby somewhat fancifully alters the 

 term prothorax into manitruncus, and calls Chabrier's " seg- 

 ment alifere^' alitr uncus ; giving to the two united the name 

 of truncus. Knoch called the prothorax " collum,'' and the 



"" Except in the order Libellidites. ° Iclineumonites, &c. ° Apites, 



p Straus-Durckheim has four parts — head, corslet (prothorax), thorax (raeso 

 and metathorax), and abdomen. 



NO. IV. VOL. I. S F 



