LABORATORY WORK, V 347 



QUESTIONS 



By what substances are the flies most attracted ? What is the par- 

 ticular quality which seems to attract? What sense (sight, smell, or 

 other) seems to have most influence? 



TOPICS FOR FURTHER STUDY 



1. The habitat and food of the fly. 2. Development. 3. Respira- 

 tion. 4. The parasites of the fly. 5. Other Diptera: Glossina 

 (tsetse-fly), bot-flies, Syrphus, horse-fly, black-fly, crane-flies, gall 

 gnats, gnats, mosquitoes, sheep-ticks or lice-flies, fleas, and jiggers. 

 6. The economic importance of Diptera as parasites on animals and 

 plants, as gall producers, as destroyers of grain, as distributers of 

 disease, and as scavengers. 



V. LITHOBIUS 



This myriapod may be obtained under woodpiles, or damp leaves 

 in woods, even in late autumn or during mild days in winter. 



DRAWINGS 



1. Dorsal view, x 5. 



2. Head, under side, naming principal parts, e.g. antennae, jaws, 

 first trunk appendages, etc. x 15. 



3. Head, upper side, x 15. 



4. Two consecutive segments seen from left side, showing legs and 

 stigma, x 10. 



QUESTIONS ON EXTERNAL ANATOMY 



1. How many segments in the body? Is the number constant? 

 (Examine two or three individuals.) Are new segments formed 

 throughout life ? Compare with earthworm. 



2. How many segments in the antenna? Is this number constant? 



3. How many segments in the leg? 



OBSERVATIONS ON THE LIVING ANIMAL 



Each student should be provided with the following: (1) a glass 

 rod as in No. VI. or toothpicks; (2) vial of cologne; (3) vial of 2% 

 acetic acid; (4) a soup-plate; (5) a pane of glass large enough to 

 cover the plate ; (6) forceps to hold Lithobius. 



