OF THE ANNULOSA. 4l3. 



racter to distinguish them than that each carries a pair of 

 true feet. And this seems the proper definition of the 

 thorax of an Annulose animal, namely, that it consists of 

 those segments which carry the true organs of locomo- 

 tion ; a rule which, if applied to Coleopterous insects, 

 will evidently make us account those articulations, appa- 

 rently the first of the abdomen, to be in reality the last of 

 the true thorax. The abdomen, therefore, of a Coleopte- 

 rous insect is in reality composed of only seven segments, 

 of which the last is often retracted from its forming part 

 of the sexual organs. M . Latreille observes, that this re- 

 traction of segments is still more remarkable in Hymen- 

 opterous insects, since the genus Chri/sis, for instance, 

 has apparently only three or four abdominal articulations, 

 the remainder being in fact internal and composing a sort 

 of tube. He also remarks that the position of the sexual 

 organs in the Apiropoda of Savigny will always be suffi- 

 cient to mark out the true thorax, except in the genus 

 Scolopendra ■ but the best method is, as before mentioned, 

 to consider the thorax as consisting in all insects of those 

 segments to which the true organs of locomotion are at- 

 tached. I say the true organs of locomotion, because by 

 this expression the false feet of Crustacea and Myriapoda 

 are excluded. 



But if the thorax of Winged insects should consist of five 

 segments, corresponding to five in Crustacea, — and the 

 inspection of the trunk of a Cetonia or Buprestis gives 

 some credibility to the supposition, — then the substitutes 

 of the two pairs of feet wanting can only be found in the 

 wings, which, in the pupa state, are disposed like the 

 feet, and which have a situation, so far as relates to the 

 thoracic segments, exactly suitable to what we should have 



