606 On the Coloration of Eggs. 



(if these views be correct) is specially entrusted with its 

 defence — at any rate in relation to an Indian Mongoose. 



The mongoose's daily food during the two months was 

 mainly meat — raw beef (almost daily), frequent heads of 

 cliickens and ducks, young chicks, &c., that had come to 

 an untimely end, sometimes mice and on a few days rabbit. 

 He also received occasional insects (chiefly Noctuid moths) ; 

 scraps ; and an egg every night — not entirely fowls^ for I 

 had some other eggs, of doubtful freshness, that I did not 

 use in experiment (except where specially mentioned) but 

 utilized for food. 



EXPLANATION OF PLATE XIX. 



The figures of South- African eggs are intended to illustrate : — 



a. Polymorphism in Weavers' eggs and their tendency to fall into 



local colour-groups with unrelated eggs (i. e., Hyphantornis 

 jamesoni, figs. 3, 6, 7, 9, 12, 15). 



b. The considerable pigmentation of some eggs laid in holes 



(i. e., Spreo bicolor, fig. 18). 



c. The extraordinarily close resemblances that purely coincidental 



variation can bring about. 



Fig. 1. Tympanlstria bicolor. Fig. 14. Pycnonotus layardi, 



2. Coitus striatus minor. 15. Hyphantornis jamesoni. 



3. Hyphantornis jamesoni. 16. Pycnonotus layardi. 



4. Crater opus kirki. 17. Anthtis lineiventris. 



5. Hyphantornis jamesoni. 18. Spreo bicolor. 



6. Dryoscopus yuttatus. 19. Erithacus swynnertoni. 



7. Hyphantornis jaynesoni. 20. Cossypha natalensis. 



8. Laniarius quadricolor. 21. Sitayra velaius. 



9. Hyphantornis jamesoni. 22. „ „ 



10. Pycnonotus layardi. 23. „ ,, 



11. „ „ 24. „ xanthoptera. 



12. Hyphantornis jamesoni. 25. „ „ 



13. Pycnonotus layardi. 



