INSECTS: THEIR BREATHING ORGANS 125 



organization, but which soon gives place to opacity, as the 

 insect advances in age. 



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

 surface of the animal is furnished at certain determinate 

 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 individ- 

 ual, 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 

 whole 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 atten- 

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

 ments to the abdomen ; at the eighth it seems to divide into 

 two branches, one longer than the other. This appear- 

 ance, however, is due to the circumstance that the respira- 

 tory 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, 



