826 



ANNUAL REGISTER, 1805: 



conic, and tipped with a tuft of 

 cartilaginous hairs : the clypeus 

 is only depressed, and thejugular 

 triangle wider : the eyes are 

 large, and very evident, those of 

 the male black, though in a ccr- 

 tain light appearing greenish ; 

 but those of the female are like 

 pearls, or as if they were covered 

 with a crystalline membrane : 

 the angles of the brim of the 

 socket are small and rounded at 

 the top, and the hinder one lower 

 than the eye. The pivots of the 

 antennas are not so discernible as 

 in the former species, being like 

 the surrounding parts in colour : 

 the under joint is without any 

 hairy papilla or wart : the upper 

 joint or clavais of the size of the 

 head, quite globular, and resem- 

 bles an inllated bladder,, being 

 almost pellucid, and of a light 

 tlesh-colour : the keel is nothing 

 more than a raised line, finish- 

 ing on the vertex in only one 

 chesnut-brown tubercle covered 

 with cartilaginous hairs : behind 

 there is a little Conical shining 

 hook, of the same colour and with 

 the same sort of hairs bending 

 outwardly, being of equal length 

 with the horn on the head, but 

 narrower : the pedicle is short, 

 straight and cylindrical. The in- 

 terior palpi, furnished with very 

 visible hinges, arc a little thicker 

 towards the top, but look, in 

 some directions^as if they were 

 filiform: themandibles have large 

 hinges, and the superior sheath 

 almost as long as the inferior one, 

 and nearly cylindrical. The tho- 

 rax is of the same breadth with 

 the head, and not very uneven, 

 the two parts being separated by 

 a furrow only on the sides and 

 underncathj the foremost above 



' and on the sides, resembling an 

 ' annular segment, and the hinder 

 ' one impressed in the middle with 

 ' a mark somewliat like two smaR 

 ' diverging wings, of a blackish 

 ' silvery colour. The elytra are 

 ' shorter than the abdomen, and 

 ' minutely punctated : the under 

 ' wings are of a shining and changc- 

 ' able violaccouf colour, and not 

 ' very dark : the abdomen has the 

 ' terminal segment a little convex, 

 ' and in the female more so than in 

 ' the male : underneath, the third 

 ' and last segments are darker than 

 ' the others, the legs arc all of equal 

 ' length ; the tarsi longer than 

 ' those of the pausus microcepha- 

 ' his, and have both the joints and 

 ' the claws much more distinct." 



Account of some Experiments on the 

 Deice?it of the Sap in Trees. In a 

 Letter from Thomas Andreio 

 Knight, Ksq. to the Right Hon. 

 Sir Joseph Banks, Burt. 



My dear sir. 



In a memoir which I had the ho- 

 nour to present to you two years 

 ago, I related some experiments on 

 trees, from which I inferred, that 

 their sap, having been absorbed by 

 the bark of the root, the trunk and 

 the branches ; that it passes through 

 what arc there called the central 

 vessels, into the succulent part of 

 the annual shoot, the leaf-stalk, and 

 the leaf ; and that it returns to the 

 bark, through the returning vessels 

 of the leaf-stalk. The principal 

 object of this paper is, to point out 

 the causes of the descent of the sap 

 through the bark, and the conse- 

 quent formation of wood. 



These causes appear to be gravita- 

 tion, motion, communicated by 



winds, 



