INTRODUCTION TO INSECTS. S 



in motion in and out of the food mass; these are the 

 palpi or feelers; one pair is attached to the labium and 

 the other pair to the maxillae. It is thought that there are 

 developed on these palpi of the grasshopper the taste 

 buds which give the insect its taste impressions, its sense 

 of relish or disapproval of thfe food under consideration. 



On the front of the head, well toward the eyes, are the 

 antennae, and these are sense organs for all insects, though 

 not giving the same sensation in all cases. Touch the 

 antenna of your grasshopper very lightly, and it gives a 

 quick jerk. Threaten without striking, and, if the insect 

 does not jump away, the same response will be given. 

 Make a loud noise near the insect's antennae, and the 

 antennae will wave about as if in response. As to other 

 insects, some use the antennas as ears, while others use 

 them as noses. The true uses of the grasshopper's 

 antennae are not known. Here is an opportunity for some- 

 one with time and patience, to discover a valuable fact. 



As to the abdomen, in most adult insects the abdomi- 

 nal segments are fairly distinct and similar, thus retaining 

 the form of the primitive type of insect ; for in insects, as 

 in all animals, the simplest form is the undifferentiated or 

 similarly-segmented type or individual. 



The insect's body wall is cuticle, but it is rendered 

 firm and homy by the addition of a substance called 

 chitin, a substance which serves for the protection of the 

 soft internal organs, and also for the attachment of the 

 many muscles necessary in running, fijang, fighting, home- 

 making, and other activities of insect life. There is no 

 internal skeleton, but the chitinized cuticle serves the 

 purpose of an exoskeleton. From this exoskeleton, 

 especially in the thorax, many processes of the body wall 

 project inward for the attachment of the muscles of the 



