of a Species of My gale. 163 



coup plus avant dans la terre." I am however inclined to infer, 

 from the similarity of one of the Corfu nests already noticed, that 

 the length of the tubes constructed by M. fod'tens probably does 

 not exceed those of M. lonica. 



Having now arrived at the lower part of the nests, it remains 

 for me to notice a very remarkable peculiarity which presented 

 itself in this portion of some of those which came under my obser- 

 vation at Zante, the extreme end within the ground being formed 

 somewhat upon the same model as the top, that is to say, being 

 provided with a second operculum of greatly diminished size, and 

 opening downwards as shown at figs. 12, 13, and 14. 



The only conjecture which I would hazard as to the use of the 

 moveable process referred to, which I should mention only oc- 

 curred in some nests, is, that it may possibly have answered the 

 purpose of a drain to the bottom of the nest; for in no other way 

 can I account for the construction of these sing\ibr portals in a 

 situation where, to all appearance, they were destined to remain 

 closed throughout the whole period of their existence. In any 

 case, however problematical the advantages to be derived from 

 this operation may at first sight appear, 1 feel no hesitation in 

 affirming, that the result of further observation will convince us 

 that the ordinary sagacity of these ingenious miners has not been at 

 fault, or deserted them in this particular instance. (See Art. XXIV.) 



It should be added, in order to avoid all possibility of miscon- 

 struction upon the subject, that although the nests figured are 

 presented as nearly as possible of natural size, I cannot affirm, 

 nor do I believe, that the parts represented, or either of them, are 

 portions of one and the same nest ; but simply that, from a num- 

 ber of nests extracted, the top of one, and the bottoms of two, are 

 here produced, the originals of which I have also brought for 

 inspection at the present meeting. 



In closing this communication I may observe, that it is recorded 

 of a species of mining spider mentioned in Brown's History of 

 Jamaica (page 420, Tarantula, No. 2), that its nests are con- 

 structed with a double doorway ; the second valve, however, 

 appearing in this case to have been at the top, and placed in con- 

 junction with the ordinary one, so as to have had but one hinge 

 in common. Brown also gives a figure of the nest (Tab. 44, fig. 

 3, and 3 — 0) with, to use his own words, " both its valves, which 

 are so well contrived, and so strongly cemented, that whenever 

 they are forced open, the native elasticity of the ligaments that fix 

 them, restore them immediately to their usual position." Another 

 nest, mentioned by Olivier (Encyclop. Meth. vol. i. (?) page 230), 



