50 Legs of Insects. 



butterflies have over 17,000. The compound eyes are motion- 

 less, but from their size and sub-spherical shape give quite a 

 range of vision. It is not likely that they are capable of 

 adjustment to accord with different distances, and it has been 

 supposed, from the direct darting flight of bees to their hives, 

 and the awkward work they make in finding a hive_ when 

 moved only a short distance, that their eyes are best suited to 

 lont; vision. 



Sir John Lubbock has proved, by some interesting experi- 

 ments with strips of colored paper, that bees can distinguish 

 colors. Honey was placed on a blue strip, beside several 

 others of various colors. In the absence of the bees he 

 changed the position of this strip, and upon their returnthe 

 bees went to the blue strip rather than to the old position. 

 Our practical apiarists have long been aware of this fact, and 

 have conformed their practice to this knowledge, in giving a 

 variety of colors to their hives. Apiarists have frequently 

 noted that bees have a rare faculty of marking positions, but, 

 for slight distances, their sense of color will correct mistakes 

 which would occur if position alone were their guide. I^ub- 

 bock's experiments prove that ants and wasps also distinguish 

 colors. This is doubtless true of all insects that love sweets 

 and are attracted by flowers. 



APPENDAGES OF THE THORAX. 



The organs of flight are the most noticeable appendages of 

 the thorax. The wings are usually four, though the Diptera 

 have but two, and some insects — as the worker ants — have 

 none. The front or primary wings (Fig. 3, A) are usually 

 larger than the secondary or hind wings (Fig. 3, B), and thus 

 the mesothoracic or middle ring of the thorax, to which they 

 are attached, is usually larger than the metathorax or third 

 ring. The wings consist of a broad frame-work of veins 

 (Fig. 3), covered by a thin, tough membrane. The main ribs 

 or veins are variable in number, Avhile towards the extremity 

 of the wing are more or less cross-veins, dividing this portion 

 of the wings into more or less cells. In the higher groups 

 these cells are few, and quite important in classifying. Es- 

 pecially useful are the cells in the second row, from the frontal 

 or costal edge of the front wings, called the sub-costal cells. 

 Thus in the genus Apis there are three such cells (Fig. 3, A, 



