164 ARTHROPODA. 



JULUS. (Thoaaand-iegB.) 



These animals are frequently very abundant under the dead 

 bark of logs or stumps, in decaying wood, and in decaying heaps 

 of grass. In the autumn they frequently congregate under 

 boards and in corners. They feed on decaying vegetable matter. 



1. Disturb a specimen and see how it rolls up. Can this 

 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? Why does it not need to move as rapidly as the pre- 

 ceding form? Do 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 preced- 

 ing 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? Why should the animal be 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 



