90 



Ants may be caught in glasses of sugar or treacle and water sunk 

 in the stages level with the material, or old bones can be placed 

 about and occasionally plunged in hot water ; while for cockroaches 

 I have never seen anything better than Chase's phosphor paste, 

 which can be spread on pieces of paper, wood, slate, or any substance 

 and placed at night where they are most frequent, removing it again 

 in the morning. Isolating stages by msans of metal saucers soldered 

 round the supports and filled with water is an excellent plan, and the 

 Orchid pan already noticed answers a similar purpose. There are 

 several insects which are peculiar to Orchids, and one of the worst 

 of these is that which attacks Cattleyas, causing the pseudo-bulbs to 

 swell, and for which the only remedy seems to be cutting the growth 

 away immediately it is seen to be swelling unusually. A useful little 

 friend in the Orchid house is the green frog, which is a most per- 

 severing and voracious destroyer of insects, and two or three of them 

 in a collection will save the cultivator a great amount of trouble. 



The diseases of Orchids are few, and are principally due to 

 excessive moisture in the air or at the roots, accompanied by unduly 

 low temperatures. Many Orchids will continue healthy with very 

 little heat, but the supply of water must be correspondingly dimi- 

 nished or decay of some kind will commence. That form termed 

 " rot " chiefly attacks the pseudo-bulbs, but sometimes the leaves, 

 and in any case the decayed portion must be cut clean out, dusting 

 the surface freely with sulphur. " Spot," which appears on the 

 leavep, has a similar origin, and the best plan is to alter the treatment 

 as to heat and moisture, cutting away the worst leaves, or dusting 

 them with sulphur. It is important to keep all material in a fresh 

 clean state, providing a wholesome atmosphere by suitable ventilation. 



SELECTIONS OF ORCHIDS. 



The number of genera of Orchids recognised in the latest authori- 

 tative work, Hooker and Bentham's " Genera Plantaru~n,*' is 334, 

 which comprise a total of about 5000 species. Of these probably 2000 

 are in cultivation, but very few collections comprise 1000 species, and 

 the majority are confined to much smaller numbers, especially where 

 quantities of one sort like Odontoglossum Alexandra? are grown. The 

 variation in habit, floral form, and colours is very great, and in no 

 generally cultivated family do we get such a remarkable range. 

 The majority of Orchids are comparatively dwarf, and in some cases 

 diminutive, as in the ' ulbophyllums, the Australian B. minutissi- 

 mum, and a Bornean species found by Dr. Beccari having pseudo- 

 bulbs one-twelfth of an inch in length and breadth, and are the 

 smallest Orchids known. From these we get many gradations to the 

 stem-producing Vandas and Vanillas, and then by a great advance to 

 Erythrorchis or Galeola, which has bare scrambling sterna sometimes 



