4(5 JHILOSOPHICAL TRANSACTIONS. [aNNO 1684. 



not SO close together as when the gut is contracted. By which means the 

 blood-vessels, lacteals, and lymphatics come more easily to receive their liquors 

 into them. 



On the Projection of the Threads of Spiders; and on Bees breeding in Cases 

 made of Leaves; also a Viviparous Fly, &c. By Dr. M. Lister. N° l60, p. 592. 



I take the forking of some threads to be merely accidental, as it is to our 

 hair, and not designedly done by the animal ; for I have observed them exceed- 

 ingly sleek and smooth. There is indeed a dividing in the projection of the 

 threads of many sorts of spiders, and especially among those which we distin- 

 guish by the name of lupi ; which tribe is most frequent and particularly delights 

 in sailing, yet this division is of a different nature from forking. These lupi 

 will dart a whole stamen or sheaf at once, consisting of many filaments, yet all 

 of one length, all distinct and divided from each other, until some chance 

 either snap them off or entangle them ; but for the most part you may observe 

 that the longer they grow the more they spread, and appear to a diligent ob- 

 server like the numerous rays in the tail of a blazing star. As for that which 

 carries them away in the air so swift, it is as formerly hinted, partly their sudden 

 leap, and partly the length and number of the threads projected, the stream of 

 the air and wind beating more forcibly upon them, and partly the posture and 

 managment of their feet, which, at least by some species, I have observed 

 to have been used very like wings or oars, the several legs being sometimes 

 close joined, and other times opened, again bent or extended, 8cc. according to 

 the several necessities and will of the animal. They cannot strictly be said to 

 fly, as they are carried into the air by external force; but they can, in case the 

 wind suffer them, steer their course, and perhaps mount and descend at plea- 

 sure; and as to the rowing themselves along the air, it is observable that they 

 always take their flight backwards, that is, their head looking a contrary way, 

 like a sculler on the river. It is scarcely credible to what height they will 

 mount, which yet is precisely true, and a thing easily to be observed by one 

 that shall fix his eye some time on any part of the heavens, the white webs at 

 X vast distance very distinctly appearing from the azure sky; but this is in autumn 

 only, and that in very fair and calm weather. Divers sorts have divers ways 

 and particularities in performing this surprising phenomenon. 



The account given of the bees breeding in cases made of leaves, Philoso- 

 phical Transactions, N° 65, exactly agrees with what I have observed. I ad^, 

 that they are not very scrupulous in the choice of those leaves, but will make 

 use even of exotic plants, such as the blue pipe or syringe-tree. There is a 



