Families of Birds 159 



Section C. Tracheophona. 



FAM. I. Dendrocolaptida. (Wood -hewers.) Nest of various 

 form, of mud or sticks and other material, often of very 

 large size on a branch, with passages ; sometimes suspended 

 from a branch, or domed in a reed-bed. Eggs white, buff, 

 or greenish-blue. South America. 



FAM. II. Formicariida. (Ant-birds.) Nest of roots or fibres 

 and moss in low bushes. Eggs bluish or white or rufous 

 brown, streaked or spotted with reddish-brown. South 

 America. 



FAM. III. Conopophagida. (Ant-Wrens.) Nest and eggs un- 

 known. South America. 



FAM. IV. Pteroptochida. (Tapacolas.) Nest of grass or moss 

 in holes in the ground, or of sticks or grass in low bushes. 

 Eggs white. South America. 



Section D. Atrichornithida. (Scrub-birds.) Nest and eggs 

 unknown. Australia. 



Such a summary of the Families and Orders of Birds as 

 I have given above comprises but a rough and general idea 

 of the characteristics of their nests and eggs, but sufficiently 

 for the purpose of our present study. A survey of the 

 different styles of colouration in the eggs of birds, even those 

 belonging to the same family, will soon convince the 

 student that, for the purpose of classification, the pattern 

 or colour of the eggs will not carry him far. Thus, for 

 instance, in the Family Hirundinida, or Swallows, the 

 general type of egg is white with reddish spots, whereas in 

 the Martins the egg is pure white ; but even in the case of 

 the latter birds there is difference in the mode of nidifica- 

 tion between the mud-built nest of a House-Martin (Ctteli- 

 don urbicd] under the eaves of a house, and the rough little 

 apology for a nest which the Sand-Martin (Clivicola riparia) 

 makes at the end of its tunnel. And this rule of variation 

 runs throughout many Families which in other respects 

 would seem to be so well characterized that uniformity in 



