cuckoos' eggs and EVOJ.TITION. 291 



green or greyish pink and the character of the markings is ahiaost 

 as varied as the ground-colour. The most common type of egg 

 undoubtedly , has the ground white to pink or pinky-grey, 

 the surface profusely covei'ed with small spots and specks of 

 reddish brown. Now evolution has produced for this Cuckoo in 

 Assam, eggs which vary from pure white with numerous small 

 specks of reddish, to deep pink heavily marked throughout with 

 vai'ious shades of reddish brown. The first type is generally 

 placed in the nests of Cisticola and agrees with the eggs of that 

 bird in all respects but size ; the second type of egg is most often 

 deposited in the nest of Suya and agrees well with the most 

 common red type of that bird's egg. 



As regards the Pipits, two species are called upon to do duty, 

 the first, Anthus richardi striolatus, a very rare bird which breeds 

 on one or two ridges only, and Anthus richardi ruftdus which 

 breeds in considerable numbers up to about 5000 feet or a little 

 higher. Here the only signs of evolution traceable are in the 

 fact that the majority of Cuckoos' eggs deposited in these nests 

 are dark and therefore do not contrast strongly with those of 

 the Pipit. 



With G. G. hakeri, blue eggs are much less common than they 

 are with 0. c, ielephonus, doubtless because suitable fosterers 

 laying blue eggs are not available. We, however, do find such 

 eggs occasionally, and these most often in the nests of either 

 Liothrix lutea or Mesia argentauris, birds which lay bright blue 

 eggs marked boldly with reddish brown or purple-black. In these 

 cases, too, we often find that the blue Cuckoos' eggs are more or 

 less spotted. It would be possible to continue instances of 

 incipient and partial evolution in the eggs of Gticulus canorus 

 and its geographical races almost ad infinitum, but perhaps more 

 than enough has been written to prove beyond all doubt that 

 the three degrees of evolution taken as a basis for this article 

 do exist. 



From Australia I have not been able to obtain any material to 

 help me much in my work. This has been because, as in 

 England, collectors vie with one another not in getting eggs to 

 prove some theory or to form a basis for another but in 

 getting eggs with a great variety of fosterer. Future work by 

 Messrs. Orton, Berthling, Archer, and others should prove of 

 great assistance and value and material should be available before 

 long sufficient to enable us to decide what is happening in 

 Australia. 



I have not commented on many other Cuckoos, the eggs of 

 which are fairly well known, such as various species of Chalco- 

 coccyas, Sierococcyx nisicolor and fugax, Penthocerycc sonnerati, 

 Sumicidus, etc., etc., as though none of these afix)rd any evidence 

 contradicting what I have written, yet none of them afibrd such 

 good instances of the various stages of evolution as those I have 

 selected for the purpose. 



Perhaps, before leaving the subject of Cuckoos and their eggs. 



