50 HALF-AN-nOUR AT THE MICROSCOPE. 



Small Fly from Greenhouse is a homopteron. If there be 

 four wings present, with two joints to each tarsus, it is a species of 

 Psylla; if two Avings, and one joint only in each tarsus, then it is 

 a Coccus. Systematic descriptions of the insects in these genera 

 are much required. Two species of Psylla may be readily pro- 

 cured for purposes of study in the summer : — One, Psylla huxi 

 (whose history is traced by Reaumur, " Memoires," Tom. III., PI. 

 XXIX., Fig. I — 1 6), causes the terminal shoots and young leaves 

 of the box tree to assume the appearance of buds. The other 

 inhabits the underside of leaves of the great nettle. Of the 

 CocctdcB, the most accessible example is the " scale-insect " infest- 

 ing leaves of the myrtle and oleander. Westwood (Intro. Mod. 

 Class. Insects, II., pp. 434 — 450) should be consulted for a 

 general view of the subject, and also from its giving references to 

 authorities who have written in detail, with figures. 



Sponge, a piece of. — The following particulars are wanting to 

 make this specimen a satisfactory demonstration, or indeed of any 

 value ; it wants to be connected with other things of a similar 

 kind. We should also be told its scientific name ; in what 

 direction the section has been made ; and from what part, near 

 the base of attachment, or the distant part of the sponge ; its 

 size and habitat (as fresh-water or marine). These particulars, if 

 satisfactorily given, would impart real value to what otherwise is 

 almost valueless. 



Sand-Blast Cells promise to be a valuable addition to the 

 means of the working microscopist. One of the most important 

 questions in mounting at the present time is. How to display 

 objects wit/iout crushing, readily, without loss of time involved in 

 making, or the extra heavy weight of glass or tin cells. Large 

 sizes will be required, and it will be an advantage to have the 

 hollow not rounded, but in every part even with the surfaces of 

 the slide. 



Bacteria in Sea-Air. — Moureau and Miquel, as a result of 

 their microscopical analyses of sea-air at various places, state that 

 when the breezes come from the sea the air is almost free from 

 bacteria. When 100 kilometres out at sea, the breezes coming 

 from the shore are almost free from them, thus proving that the 

 sea is an insurmountable barrier to contagion. 



Exchange. — Well -mounted Slides of Foraminifera, Echinodermata, 

 Polyzoa, Diatomaceae, Fish-Scales, Crystals, and Spicules ; in exchange for 

 other well-mounted Slides. Lists exchanged.— W. M. Ranson, The Cottage, 

 Priory Road, Anfield, Liverpool. 



