INTERNAL ANATOMY OF INSECTS. 99 



Reaum.), which laps over and defends all the viscera of 

 the animal, and goes principally to the formation of the 

 imago a . I have said that Cuvier conceives nutrition in 

 insects to take place by imbibition or immediate absorp- 

 tion ; that is, I suppose, the different parts and organs 

 thus constantly bathed in the blood, imbibe from it the 

 particles necessary for their constant accretion. M. Cha- 

 brier seems to think that it is the compression and di- 

 latation of the trunk that duly distributes the nutritive 

 fluid b ; Lyonet compares the nutrition of insects by 

 their fibres from this fluid, when formed into the corps 

 graisseux, to that of plants that draw their support by 

 their roots from the earth c . Much obscurity, however, 

 at present rests upon this subject much for future 

 investigation to explore ; but in all the works of the 

 MOST HIGH there is always something inscrutable, 

 something beyond the reach of our senses and facul- 

 ties, which teaches us humbly to adore his infinite per- 

 fections. 



II. The circulation of the Arachnida is next to be 

 considered ; and the term applied to these becomes 

 strictly proper. Two great tribes, in our view of the 

 subject, constitute this Class, the spiders (Araneidea) 

 and scorpions (Scorpionidca) : I shall give you some ac- 

 count of the circulating vessels of each. In spiders, the 

 heart in general is a long dorsal vessel as in insects, but 

 supposed to be confined to the abdomen, growing slen- 

 derer towards each extremity, particularly the anal. In 

 some also, as in Aranea domestica, like that of insects, it 

 has lateral muscular appendages ; but in others, as in 



a Cuv. Anat. Comp. iv. 158. Herold Schmetterl. 2S. 



b Sur le Vol des Ins. c. iv. 88. note 1. c Anat. 428. 



H 2 



