COCOON LIFK AND ISAUYIIOOD. 249 



example, tlmt of Atypus piccus, as sliowii Ijy Mr. F. Enock, and Uial of Eury- 

 pclina liL'iitzii, as I have dcnioiistrak'd by several species), that tlie Tra})- 

 door spiders may live for several years at least. Mr. Moggridge was 

 inclined to think, judging from the character of the nest and its sur- 

 roundings, that some which he saw had been occupied more than a year. 

 Evidence of enlargement of the door is not rare to meet with, though, as 

 a I'ule, the new piece is woven on to the old with such neatness as more 

 or less to obscure these. Exami)les were found in which the old and 

 smaller door of Nemesia meredionalis was i)artia]ly attached to the large 

 new door which had been constructed below it. 



This view is borne out by the fact that a cork trapdoor may be readily 

 separated into a number of layers of silk, with more or less of earth be- 

 tween every one. These layers deci-ease in size from witliout 



_ , inwards, and together form a sort of saucer in wliicli the small 



Last f , 



Doors central mass of earth 



lies. (8ce Fig. 2G4. 

 By moistening a series of the 

 cork trapdoors of Nemesia ce- 

 mentaria, Moggridge was able to 

 detach, in one of medium size, 

 from six to fourteen circular 



patches of silk, of which the #%n ..-^^ ,-^5% ^."-.^r^ ^v^. ^^, ^,., 

 outermost, or that which forms |C:# ^^ij i:^ fe#%;ilC^Cl O ® 

 the lower surface of the door, 



was the largest, and the inner- ^'"^ ^^- successive layers in formation of a trapdoor. 



V ' _ (After Moggridge.) 



most the smallest, thus being in- 

 termediate in size as in position. The last and smallest appears to be the 

 first door the spider ever made, and the consecutive layers mark successive 

 stages in the enlargement of the nest. Baron Walckenaer found more than 

 thirty alternate layers of silk and earth in the nest of Cteniza fodiens.'-^ 



Moggridge was confirmed in his opinion that these layers mark a suc- 

 cessive enlargement of the nest, by the additional fact that in very small 

 doors they are few or single, and a proportion is observable between the 

 size of the door and the number of laj'ers of which it is composed.^ 



In order to test whether the doors were enlarged or not, Moggridge 

 measured the surface doors of seven double door nests, and one minute 

 cork door, on April oOth. On the 8th of October following he measured 

 all these nests once more and found that they all were enlarged, the aver- 

 age rate of increase being one and seven-tenths lines in the five and one- 

 half months which had elapsed. The highest increase of the eight was 

 from live lines across to seven and one-half lines across. In none of the 



^ After Moggridge, pi. xiv., and page 193. ^ Apt,, Vol. I., page 228. 



^ Trapdoor Spiders, page 125, aud table from twenty-eight specimens examined, page 150. 



