_Measured April 30, 1872._ | _Measured Oct. 18, 1872._ | No. I. 9 lines across | No. I. 10-1/2 lines across II. 4 " | II. 5-1/2 " III. 4-1/2 " | III. 5-1/2 " IV. 4 " | IV. 4-1/2 " V. 2 " | V. 3 " VI. 2-1/2 " | VI. missing VII. 1 " (the cork) | VII. 2 lines across VIII. 5 " | VIII. 7-1/2 " We can scarcely venture from such limited premises to draw any precise conclusions, but if we suppose that during the entire course of the year the nests increase on an average by about four lines in diameter, and assume that the rate of growth continue the same, the nest of the infant spider, whose surface door measures scarcely a line across, would still require four years to attain the dimensions of some of the largest double-door nests, whose surface doors measure sixteen lines across. It seems to be the rule with spiders generally that the offspring should leave the nest and construct dwellings for themselves when very young. Mr. Blackwall,[86] speaking of British spiders, says:--"Complicated as the processes are by which these symmetrical nets are produced, nevertheless young spiders, acting under the influence of instinctive impulse, display, even in their first attempts to fabricate them, as consummate skill as the most experienced individuals." [Footnote 86: Loc. cit., p. 11.] Again, Mr. F. Pollock[87] relates of the young of _Epeira aurelia_, which he observed in Madeira, that when seven weeks old they made a web the size of a penny, and that these nets have the same beautiful symmetry as those of the full-grown spider. Those of the latter are vertical, circular, made of about 250 feet of thread, having about 35 radial lines and 38 concentric circles, the outermost of which is some 20 inches in diameter. After the lapse of a day or two the web loses its adhesive property and a new one is made. In about six months the female _Epeira_ has completed her ten changes of skin, one of which takes place in the cocoon, and "at the end of eight months the spider is 2700 times as heavy as at its birth." This _Epeira_ lives, we are told, for about eighteen months. [Footnote 87: The History and Habits of _Epeira aurelia_, in Annals and Mag of Nat. Hist. for June, 1865.] One can scarcely contemplate the work of these architects and weavers, and especially of the trap-door makers, without being carried away into the whirlpool of discussion which has so long raged round the word _instinct_. Do the young spiders build their first nest by instinct--that is to say, independently of all teaching or personal experience--or do they copy the nests in which they were hatched?