jULus. 153 



mal to run and see how the legs are used. Do those of a side all 

 move in the same direction at the same time? Are all of the 

 legs alike? Notice the pair of appendages just behind the head 

 and see how they differ from the others. These appendages are 

 organs of prehension that are used in grasping the prey. They 

 are provided with poison glands that open on their inner sides 

 near their free ends. 



3. Examine the head and find the eyes, antennoe, and mouth 

 parts. The latter consist of a labrum, a pair of mandibles, and 

 two pairs of maxillce, the last pair of which are united to form a 

 labiutn. 



4. Understand how the animal breathes. The stigmata are 

 situated near the bases of the legs, but are hard to see except in 

 favorable specimens. 



Make a drawing of the animal. 



JULUS. (Thoosand-Ie^s.) 



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. 



