INSECTS: THEIR BREATHING ORGANS. 105 



Very curious, too, are the hairs with which the whole 

 surface of the animal is furnished at certain definite 

 points. But these are seen to more advantage in 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 second- 

 ary 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 whole body ; there is a tuft on each 

 antennae ; 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 atten- 

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

 segments to the abdomen ; at the eighth it seems to 

 divide into two branches, one longer than the other. 

 This appearance, however, is due to the circumstance that 

 the respiratory tube is sent forth from the eighth segment, 

 and that the ninth and tenth segments are bent away at 

 an angle from the general line of the body. 



The ninth segment is very small : the tenth is squarish, 

 with rounded corners, and is brought to a thin edge. 

 Around the margin there is the most exquisite array of 

 hairs possible ; at one corner there are three pencils ; 

 while round the opposite and down the corresponding side 

 run, in two rows, twelve pencils set very close to each 

 other, and each containing a large number of very slender 

 hairs. The extreme end of the segment is ornamented 

 with four diverging organs of taper conical form and 

 crystalline clearness, through the midst of each of which 

 passes a very fine branch of the air- tube system, which 

 gives off still more attenuated branchlets in its course. 



