ABDOMEN. 293 



of the ichneumons, the sword of the grasshopper, and the 

 sting of the bee, exhibiting some of their chief modifications. 

 Besides these, the extremity of the abdomen is sometimes fur- 

 nished with additional appendages, such as the forceps of the 

 earwig, common to both sexes, but considerably larger in the 

 male than the female), and of the scorpion-fly (Panorpa), in 

 which it is only found in the male : the long and slender 

 threads of the may-flies (Ephemerce), which seem to be of 

 service to these insects in their alternate rising and falling 

 flight, being brought into contact when ascending, but ex- 

 panded during the descent ; other shorter and broader ap- 

 pendages are found in the dragon-flies, cockroaches, spectre- 

 insects, &c. Sometimes these appendages are articulated, 

 in other insects simple and entire. 



We have now brought our review of the external organiza- 

 tion of insects to a close. That it has extended to a con- 

 siderable length I am aware, and that it must be, to a 

 certain extent, comparatively uninteresting to many readers, 

 I much fear; but it appeared impossible to dismiss the 

 subject at shorter length, consistent with the increased num- 

 ber of organs exhibited to us by insects, and which so far 

 exceed those of the higher animals. I have endeavoured, 

 as far as possible, to keep clear of those minute details which 

 may be said to have reference to a specific instead of a gene- 

 ral sketch of Entomology. I have, therefore, in the next 

 place, to direct attention to 



Sub-section 2. The Internal Anatomy of Insects. 

 Having already stated that the skeleton (upon the varia- 

 tions of which much importance is placed in the higher ani- 

 mals) is in insects external, we at once perceive that our 

 labours on arriving at the internal anatomy of the latter 

 are considerably diminished. 



This, indeed, is one of the chief charms of this 



c c3 



