90 A HALF- HOUR WITH THE 



will be found to consist, at its extremity, of a little 

 sac surmounted with hooks. These hooks are 

 represented in figure 223, plate 8. 



The wings of insects, too, are beautiful objects \ 

 easily investigated by a low power. The nerves 

 which run through them are supplied with tracheae, 

 and they thus become organs of respiration. The 

 under wing of the bee is supplied with a series of 

 hooks, seen at figure 211, plate 7, which slide on 

 a thickened nerve on the upper wing, marked a, 

 and keep the wings steady during flight. 



The lepidopterous insects, including the butter- 

 flies and moths, have got their name from the scales 

 on their wings. These scales assume a wonderful 

 variety of form, and claim a large amount of atten- 

 tion from the microscopic observer, and cannot be 

 neglected by the entomologist. 



The little blue argus butterfly has scales in the 

 shape of a battledore, drawn at figure 225, plate 8, 

 the handle being the part attached to the wing. 

 All the scales have handles of this sort, whatever 

 be their shape. At figure 226, a scale of ordinary 

 shape is represented. Sometimes the scale is broad 

 at the base, and pointed at top. In the meadow- 

 brown butterfly, the point is surmounted with little 

 clubbed projections, drawn at figure 227. Scales 

 are found on other insects besides moths and butter- 

 flies : thus they are found on the common gnat. 

 These are shown at figure 228. Besides their 

 curious forms, the scales are marked with lines 

 which are exceedingly delicate, and require the 

 highest powers of the Microscope to bring them 

 out. Some of the scales are thus used as tests for 

 the powers of the Microscope. 



Just as we have seen in the tongues and legs of 

 insects, the same parts expanded or compressed 

 according to the wants of the animal, so we find the 



