INSECTS: THEIR BREATHING ORGANS 119 



from the toughness of its skin, "leather-coat." It is the 

 larva of the Crane-fly (Tipula oleracea), so familiar to us 

 under the sobriquet of Daddy Long- legs. I can easily 

 procure one of these, for, unfortunately, they are but too 

 ubiquitous. Here is one who shall have the honor of 

 being martyred for the benefit of science. Before we assas- 

 sinate him, however, just look here, at the hinder extrem- 

 ity of his body, where there is an area, surrounded and 

 protected by several points, and, in this area, two black 

 spots. 



With the dissecting- scissors I have carefully cut out 

 one of these specks, and now I put it under the Lieber- 



SPIRACLK OP LEATHER-COAT. SPIRACLE OF COCKCHAFER-GRUB. 



kuhn, for illumination on the stage of the microscope. 

 There is, first of all, a dark horny ring of an oval figure, 

 a little way within which there is an opaque, dark plate 

 of the same figure, but smaller, occupying the central por- 

 tion of the area. The space between the margin of the 

 plate and the bounding ring is occupied by a series of 

 slender filaments, placed side by side, proceeding from one 

 to the other, through the interstices of which the air is 

 filtered. The central plate seems to be quite imperforate. 



