LABORATORY WORK, IV 345 



3. From which segments do the wings arise? The legs? 



4. Of how many segments is each foot composed ? 



OBSERVATIONS ON THE LIVING ANIMAL 



1. Place a beetle upon a piece of white paper; observe the order of 

 movement of the legs in locomotion, and record by some graphic 

 method. 1 Analyze the movement of a leg of each pair; how does 

 it help the animal to move? Compare with grasshopper. 



2. Placing a bit of potato leaf (or other green leaf) at the mouth of 

 the beetle, notice the movements of the mouth-parts in feeding. 



3. Observe and record the movements of the feet of the larva in 

 locomotion. 



TOPICS FOR FURTHER STUDY 



1. Stages in the development of a beetle. 2. The principal classes of 

 beetles : illustrate, e.g., runners, divers, short-wings or rove-beetles, 

 carrion-beetles, wool-beetles, stag-beetles, tumble-bugs, May-beetles, 

 boring beetles, snappers, 4 fireflies, bark-beetles, weevils, buck-bee- 

 tles, leaf eaters, ladybirds. (Examples of these should be shown and 

 students encouraged to collect and classify them.) 3. The food of 

 beetles. 4. Economic importance: (a) injurious beetles destructive 

 to vegetation, to wood, to grain, to meat, to fur and cloth, to useful 

 animals ; (//) useful beetles advantageous by acting as scavengers, 

 by killing injurious insects. 



IV. HOUSE-FLY OR BLUEBOTTLE FLY (Musca domestica 



and ]\I. vomitorid) 



To get larvae of the bluebottle fly it is only necessary to expose 

 flesh, even on a warm winter day, a week or so before the larvae are 

 needed for class work. The larvae may be fed upon bran, and when 

 well grown may be prevented from pupating by being kept at a tem- 

 perature slightly above the freezing-point. 



1 An excellent method, proposed by Professor F. E. Lloyd of Teachers' 

 College, New York, is to have the beetle walk from an anilin ink pad (ordi- 

 nary stamping pad) to the paper. The ink on the feet will leave a print of 

 the steps on the paper. 



