78 TO CAUSE THE HYDRANGEA HORTEN8IS TO FLOWER BLUE. 



tin tubes, as traps for these rapacious enemies of the Dahlia and 

 Carnation, the inefficacy of which was complained of by " Crito," 

 in October, 1833. As an excellent trap, the service whereof I 

 have proved, I would recommend that pieces of Alder (of which 

 withered sticks may easily be obtained at this time of the year), 

 about half an inch in diameter, and with the pith pushed out, or 

 the flowering stems of the Lupinus polyphyllus, should be cut into 

 six-inch lengths, and concealed in different parts of the Dahlias. 

 At the approach of day, the insects will retire into these traps, and 

 if they be examined every morning, greatnumbersmay be destroyed. 

 Aphidep, or Plant Lice. — There is an insect of the Coccus 

 genus, which has various names in different parts of the country ; 

 such as God's-cows, Lady-birds, Lady-cows, &c, which are often 

 ignorantly destroyed on account of its being supposed to be inju- 

 rious to plants ; whereas, whatever little peculations it may occa- 

 sionally indulge in, are amply compensated for, by its rapacity in 

 its larva state for the Aphis ; so well known is this to naturalists, 

 that it has received the cognomen of Lion of the Aphides. In the 

 early part of last summer, I had several Hollyhocks in my garden* 

 whereof the under surface of the leaves were covered with the 

 Aphis ; here they would have nested as it were, and afterwards 

 slowly distributed themselves over the garden ; one morning, how- 

 ever, I observed a number of dark grey wingless insects, about 

 three-eighths of an inch long, running over the leaves with great 

 rapidity ; within a week from their appearance, not an Aphis was 

 to be found on the plants. 



Henrietta. 

 London, Feb. 5, 1836. 



ARTICLE V. — To cause Ihe Hydrangea hortensis io 

 flower Blue. By Mr. Maud, Gardener to the Rev. 

 G. Wray, Bramhope Hall. 



The Hydrangea hortensis has a place in most collections 

 throughout England. When grown to perfection, it forms a fine 

 plant for the greenhouse during the summer months, amongst the 

 tender annuals ; it is also a showy shrub in a conservatory, and 

 beautiful in the vestibule. 



