THE MICROSCOPE. 



259 



shall be astonished to find how much may be learnt with little 

 trouble. Nay, I will put it more strongly, and say. How much is 

 constantly passing before us, calculated to make the most prosaic 

 life one of unceasing interest ! I have been running over the list 

 of natural orders of insects in Westwood, and find, as I thought, 

 that from the windows alone of my house in the country, examples 

 of every order, from the highest to the lowest, of very many 

 genera, and of a large number of species have been procured. 



The e7iiire wing should always be mounted, which is best done 

 by cutting it out carefully with a handled needle (see PI. XVII., 

 Fig. 7), ground down on a hone, to make a cutting-instrument. 

 The fly being held in the left hand, and a watchmaker's eye-glass 

 used, the work to be done may be clearly seen. There is attached 

 to the base of the wings, behind, a pair of small membranous 

 appendages, termed alulae, or winglets, of a whitish colour. And 

 they are best displayed when mounted dry, with the free end of 

 the wing pointing to the left hand, the direction whence the light 

 comes. The lovely iridescent hues thus obtained make it a 

 splendid object, and the " ridge and furrow " arrangement of the 

 membrane, to secure the utmost effect when beating the air in 

 flight, is very beautiful and deserving most thoughtful study. 



Batrachospermum moniliforme (PI. XXIV., Figs, i, 2, 3) was 

 preserved in prime condition, and the different parts are well 

 and clearly seen. 



Hairs on Frond of Elk's Horn Fern (PI. XXIV., Figs. 4, 5). 

 — Though the form of the hairs is stellate on both surfaces, a 

 marked distinction will be seen between those seated on the front 

 and back of the frond respectively. The former are few in 

 number, scattered, with mostly eight long-drawn-out rays. The 

 latter form a dense pile, packed as closely as they well can be. 

 The rays are more numerous, varying in number from ten to 

 thirteen, and are also shorter and stouter. There can be no 

 doubt these differences are connected with the relative amount of 

 exposure to light, heat, and moisture of the two surfaces. It will 

 be interesting to note the character of plant-hairs on the opposed 

 surfaces of leaves at every opportunity in this connection. Cor- 

 responding differences to those here observed are well marked in 

 Deutzia scabra and the ^Mealy Guelder Rose. 



A Law to make the destruction of barberry bushes obligatory in 

 France, Spain, Italy, and Switzerland, except for ornamental pur- 

 poses in gardens and parks, on account of the cecidium promoting 

 the increase of wheat-rust, is being urged by the French National 

 Society of Agriculture. 



