200 ARTHROPODA 



be protective? See if there is any odor when it is disturbed. 

 What purpose can such an odor serve? 



2. What is the shape of the body? Is it hard or soft? 

 How many segments are there? 



3. How many appendages are borne on a segment? Do all 

 of the segments bear appendages? Does the animal move 

 rapidly? Does the first pair of appendages behind the head 

 show modifications for prehension? Does this animal need 

 such an organ? 



4. Compare the organs of the head with those of the pre- 

 ceding form. 



Make a drawing of the under side of one segment. 



Williams: Habits and Structure of Scutigerella immaculata. Proc. Bost. 

 Soc. Nat. Hist., 33, 1907. 



INSECTA 

 ACRIDIUM (Grasshopper) 



Study grasshoppers as they occur in nature and determine 

 as far as possible the following points: 



1. Do they see or hear? Are they equally sensitive to 

 touch on all parts of the body? Are these animals well pro- 

 vided with sense organs? 



2. What is their food? Are all plants eaten or are some 

 avoided? See how the mouth parts are used in feeding. 



3. What are the important enemies of grasshoppers? How 

 do they escape their enemies? Do they hide? Are they pro- 

 tectively colored? How does jumping serve them better than 

 crawling? How many times its length can a grasshopper 

 jump? 



4. During late summer and autumn you may find indi- 

 viduals depositing eggs. See if you can determine how the 

 end of the body is worked into the ground. 



For study it is desirable to use a rather large, freshly 

 killed or alcoholic specimen. 



The body is divided into three well-marked regions. 



