THE society's NOTE-BOOKS. 243 



Sphagnums. — The division of Sphagnums into acute and 

 obtuse leaved is a thing of the past. I'hey are now divided 

 according to habit and leaf structure, and many of the principal 

 specific differences are obtained from the stem leaves. There is 

 no species now called compactiun^ a more intimate knowledge of 

 the structure and variations of this interesting class of mosses 

 having proved that many of the species have varieties which 

 assume this compact form, l^hus we have S. cyjiibifolium var. 

 compactiun^ S. rigidum, var. compactwn^ etc. etc. It is not safe to 

 ^attempt to discriminate species by means of a single branch. Dr. 

 Braithwaite, in his monograph of the genus, lays considerable 

 stress on the position and arrangement of the chlorophyll cells, 

 which may be seen with a high power and in a section of the leaf. 



Chas. p. Hobkirk. 



The chlorophyll granules may be distinctly seen with the 

 ;|-inch objective. 



A. Hammond. 



Bees. — A member asks for a description of the different sorts of 

 bees. I think he can scarcely be aware that there are upwards of 

 three hundred varieties in Britain alone ; so that, a bee being 

 found, it is by no means easy to make out its specific name. It 

 is, however, tolerably easy to make out the family to which it 

 belongs. 



The first thing to be done is to ascertain to which of the two 

 great divisions it belongs : i.e.^ to the short-tongued or to the long- 

 tongued. In the first division the tongue is shorter than the 

 maxillae ; in the second the tongue is longer than the maxillae and 

 folded beneath. 



The short-tongued bees are then divided into those having 

 hairs on the posterior tibiae and those without such hairs. 



Bees having polliniferous hairs are divided into such as have 

 two submarginal cells in the upper wings and those having three 

 submarginal cells. 



Of those having two submarginal cells there are only two 

 famihes, viz., (i) Macropis, with short and dense polliniferous 

 hairs on the tibiae and plantae ; and (2) Dasypoda, where the 

 legs are slender, and the hairs dense and long. 



Of those having three submarginal cells there are four 

 families : — (i) Colletes, abdomen truncate at base ; (2) Afidretia, 

 abdomen ovate and entire at apex, with maxillary palpi as 

 long, or longer, than the maxillae ; (3) Cilissa, like Aiidrena, but 

 having the maxillary palpi only half the length of the maxilh^ ; and 

 (4) Halictus^ where the abdomen has a vertical incision at its apex. 



