INSECTS : THEIR ERKATIIING ORGANS. 119 



(hus evidently are engaged in collecting food from the 

 water ; tliongli, even witli this jjower, we can see no 

 solid matter taken in, till we discern it agglomerated in 

 tlie swallowed pellets : — the body, or abdomen, with its 

 ten joints, all (with a slight exception) the comiterparts 

 of each other ; and each carrying its own dilatation of 

 the dorsal vessel, and its own portion of the long and 

 Av ell-filled intestinal canal : — all these, I say, are very 

 interesting and cnrioiis to observe ; especially when we 

 select, as I have done, a young individual for examina- 

 tion ; since the tissues then possess a translucency 

 which is essential to our seeing with distinctness any- 

 thing of the internal organization, but which soon 

 gives place to opacity, as the insect advances in age. 



Yery curious, too, are the hairs with which the 

 whole surface of the animal is furnished at certain de- 

 terminate points. But these are seen to more advan- 

 tage ill an older specimen ; for, in this one of tender 

 hours, they are nearly simple ; whereas, in an opaque, 

 nearly full-grown individual, every hair is seen to be 

 studded with secondary points, that project from its 

 surface throughout its length. These hairs are arranged 

 in beautiful radiating pencils or tufts, and scattered, as 

 I have said, at definite points over the Avhole body ; — 

 there is a tuft on each antenna ; one on the forehead ; 

 one in front of each eye-spot ; several circles of them 

 set round the thorax ; one circle of scanty pencils set 

 round each segment of the body, and a few smaller 

 tufts scattered about besides ; all of them springing 

 from minute round warts. 



The extremity of the abdomen deserves, however, a 

 separate investigation, and we will now direct our at- 

 tention to the tail-end of our tiny grub. There are ten 



