=Cocoon.=—The last important spinning operation which remains to be described is the building of the so-called cocoon. This must be distinguished from the cocoon of insects, which is a protective covering of silk within which the larva assumes the pupa form. In the case of the Spider, the term is applied to the structure which serves to protect and conceal the eggs. It is often of considerable complexity, and is highly characteristic of the particular species which constructs it. All egg-bags are commenced in very much the same way. A small sheet of silk is woven, and against this, sometimes upon the upper and sometimes on the under surface, the eggs are deposited, and then covered in with a second silken layer. The compact silk-covered ball of eggs is then, in many cases, enclosed in a small compartment which the spider builds with infinite care and unfailing uniformity, after the pattern peculiar to its kind. A considerable number of the Orb-weavers are content with a simple silken case closely investing the eggs, and by its thickness and the non-conducting quality of the material, sufficient protection is afforded against inclement weather. The egg-bag of the large Garden-spider (_E. diademata_) may be recognised by its great size and its yellow colour, which is deepened by the still more yellow tint of the eggs within. Those of _Zilla x-notata_ and of many other English Epeirids are of similar structure, but of white silk. The mother generally avails herself of some natural shelter, hiding her cocoon beneath loose bark, in the crannies of masonry, or under the copings of walls. Many species, on the contrary, boldly expose their cocoons in their snares, sometimes as many as fourteen being constructed in succession and strung in a chain. The American species _Epeira caudata_ and _E. bifurca_ are good examples of this habit, stringing a chain of characteristic cocoons upon the line connecting the retreat with the web. The sedentary Theridiid spiders usually suspend their cocoons in the neighbourhood of their irregular snares. The green cocoon of _Theridion sisyphium_ is generally more or less concealed by an accumulation of débris. The minute species _T. pallens_ constructs a cocoon of peculiar shape on the under surface of a leaf (Fig. 196, B). It is a conical structure of white silk, considerably larger than the spider itself, attached at its broad end,[280] and having several curious lateral projections near the middle.