INTRODUCTION TO INSECTS. 3 



to serve some special purpose, as in the honey bee. The 

 segments composing the head are, in most insects, so 

 fused as to form a single box-like head-covering of one 

 sclerite only. In the larva, the separate head sclerites are 

 usually to be found. The three segments forming the 

 thorax are, in many insects, so fused as to be separated 

 with difficulty; but are observable in the generality of 

 insects, being seen most easily on the under side of the 

 body. Catch two or three large jumping grasshoppers, 

 the sort that do not fly so well as they jump. Put one into 

 the killing-bottle and let it stay there while you examine 

 the others. Seize one of them by the abdomen — carefully 

 — and you will be likely to realize the strength of the 

 muscles of its strong hind legs. If human beings were 

 able to kick as vigorously in proportion to their size, woe 

 to their enemies ! There would be left neither vestige nor 

 trace. Let the hopper try its jaws on your finger, and 

 you will sense the efficiency of leverage in the jaw muscles. 

 Set it on the table and measure the length of its jump. 

 This indicates good muscle, and stiff skeleton for fasten- 

 ing the muscles to. All grasshoppers are injurious, so no 

 harm will be done by putting these into the killing-bottle 

 after finishing the experiment. Now take out the other 

 hopper from the killing bottle, and with a sharp knife 

 sever the thorax from the abdomen ; cut off the head also, 

 and let fresh water run through the thorax till all the soft 

 internal parts are washed away. What is left will be 

 chiefly muscular tissue, the complex muscular system of 

 the thorax. Accompan3dng these muscles may be seen 

 the white fibers of the nervous system, but the muscular 

 tissue may be plainly seen, part of it consisting of strands 

 fastened to the top sclerites of the thorax, part fastened 

 to the sides, and part crossing to reach.the first joint of the 



