194 SUPPLEMENT TO 



the first door the spider ever made, and that the con- 

 secutive layers mark successive stages in the enlarge- 

 ment of tlie nest. 



There is therefore a broad distinction as to con- 

 struction between cork nests and wafer nests ; more- 

 over, while the former are, as far as we know at 

 present, all of one type, and only differ in size or 

 proportion, the latter appear under five distinct types. 



Thus, every known cork nest, wliether found in 

 Europe, America, or the Antipodes, has the same 

 solid door and simple tube; while of the wafer nests, 

 some have branched and others simple tubes, and 

 some again possess a lower door in addition to the 

 upper or surface door. 



In the following pages I intend to treat of the 

 trap-door spiders and their nests in the same order in 

 which the latter are placed in the diagram, com- 

 mencing with those of the cork type B, and then 

 dealing successively with the several wafer nests from 

 C to Gr. We have already spoken of A, the nest of 

 AU/pus piceus, and seen that our present knowledge of 

 this nest, of the habits of its occupant and of those of 

 its relations, is still far from complete. 



The cork type is, as my readers will perhaps re- 

 member, the great cosmopolitan type which ranges 

 round the world, and which, curious to say, is built by 

 many different spiders belonging to distinct genera. 



The idea of planning this very perfect bit of me- 

 chanism appears to be the common inheritance of 

 these several spiders, separated though they are by 

 wide intervals of geographical space as well as ot 

 structural divergence. 



