5 8 ABDOMEX. 



III. Composition^ or Structure. — Each ring of the 

 abdomen is composed of several pieces, or segments^ 

 of v.'Iiieh, lliough many are spoken of in technical works, 

 it vrill suffice our jjnrpose to mention hut four, i. e,, the 

 dorsal, ventral, and ri<//it and left lateral. 



IV. /Shape. — The ahdomen is usually triangular 'with 

 the point more or less obtuse, though there are many 

 special f(.>rms varying from a simple spherical or ovoidal 

 figure, to the most curious shapes, a description of Avhich 

 can scarcely be given in word, but Avhich may be readily 

 observed in the many specimens that in summer gratui 

 tously offer themselves for our inspection. The Sub-Order 

 of Hymenoptera furnisli the greatest variety of these. 



Y. Tlie clot/iinff, or covering of the abdomen, is also 

 especially adapted to the habitat and modes • f life of the 

 insect, whether in the form of horny plates, membrane, 

 hair, etc. 



YI. A2')p>endages, or Special Organs. — There are two 

 sets in particular that demand our attention, i.e , Organs 

 of Respiration and Organs of Ovip)osition, including 

 stings and a variety of instrument. 



As the special organs of respiration will again be ad- 

 verted to in connection Avith the internal anatomy of the 

 insect we will here merely mention the pair of round 

 eye-like disks that appear on the lateral segments of each 

 abdominal ring — these are the stomata, or the exterior 

 openings of the spiracles, or breathing tubes, through 

 which the insect breathes. 



The Ovipositors, or Organs of Oviposition, assume 

 a great variety of forms and functions. They some- 

 times consist of a simple j^erforating tube, for the making 



