RECENSIO CONTRADICTORIA. 



Mcetinoplaces. — Young Birds meet at certain places before starting. 

 Emperor Frederic. 7. Each species always associates separately. 

 Emperor Frederic. 8. 



Migration (Passage). 



Altitude of: Very high. Brehm Ch. L 5. — Homeyer. 5. — 

 25000 to 35000 feet. Gatke. 7 Generally lower than 1000 Metres. 



LUCANUS 1. 



Causes of: Hunger and love. Brehm A E. 4. — Food. Weis- 

 MANN. 10 Quest for richer food. Parker. 2. Food and safety. 

 Martorelli. 3. -"-Alimentation. Menzbier. 3. — Readiness to change 

 the locality. Martorelli. 1. — Northward, breeding: southward, food. 

 Martorelli. 12. — Tristram. 3. — Change of temperature, subsis- 

 tence. Emperor Frederic. 6. — Warmth, light, propagation, homing 

 sense, sociableness, currents of air. Homeyer. 18. — Not explicable 

 by want of food or currents of air. Brehm Ch. L. 15. Propagation and 

 food. Jenner 1 . Temperature, food, wandering instinct, homing faculty. 

 Faber 1, 6. — Neither warmth nor want of food, but power to foresee 

 weather. Brehm, Chr. L 14, 15. — Neither nourishment nor tempe- 

 rature, but only instinct, augmented by unconscious experience. Erk- 

 STROM. 1. — Food, temperature and sexual instinct. Pogoendorff. 1. 



— A marvellous presentiment. Brehm, Chr. L. 1. Temperature 

 probably only, anyhow main cause. 1. Temperature no cause. Angot 1. 

 Chief reason food. Hartwjq 1. 



Direction of: — S. N.,— W. E., S. W.— N.E., E.N.-W.S. etc. — 

 Influence of coasts and streams. Heuqlin. 3. — Influence of coasts 

 and. islands. Kjaerbolling. 1. Influence of rivers and valleys. Brehm, 

 A. E. 2, 3. — Rivers are crossed. Kessler. q. 



Evolution of: Migratory Birds originated from sedentary. Faber. 5. 



— Migration originated from straggling (imperfect Migration.) Weiss- 



sa 59 sg 8' 



