46 



surface of the leaves. The larvjB work in' the leaf, between the upper skin and 

 the lower, consuming the parenchyma. The}" are, when full grown, a quarter of 

 an inch long, translucent in appearance, pointed at the head, which is furnished 

 with black nippers, and truncated at the other extremity. To pupate they leave 

 the plant and enter the soil. The pupa-case (puparium) is chestnut brown. From, 

 it the fly escapes in about twenty days. (See Dr. Lintner's 1st Annual Report 

 on the Insects of New York State.) 



The method of dealing with this insect is plainly to break ofl the affected 

 leaves and to crush them under foot, or throw them into boiling water. 



Lice (Order, Hemiptera). 



The Bean Louse (Aphis fahoe ?). — A few years ago I found on some Mazagan 

 beans that I was growing in my garden at Cowansville, a cluster of plant lice. 

 They were lead-coloured and rather large. I had read of the marvellous increase 

 of the Aphis, and I resolved to let these specimens on my beans live out their 

 life and have their own way. The consequence was, that in a few weeks the 

 whole row of beans — and it was a long one — was blackened with Aphides. This 

 was quite in accordance with Reaumur's statement that one aphis can produce 

 about 90 young ones, and that in five generations the increase from the one will 

 amount to 594^,900,000. As the season went on great numbers of the larvae of one 

 or two species of Lady-birds (Coccinellidae) appeared on the scene and worked 

 great havoc amongst the hosts of the enemy. . 



In dealing with a pest such as this, watchfulness and promptitude are re- 

 quired. The first clusters of the aphis should be picked off and destroyed. 



The Cabbage Louse (Aphis brassicce, Linnaeus).— This insect is often very 

 abundant. It is found on the under side of cabbage leaves, and has a whitish,, 

 mealy appearance. 



Dusting lightly with flour of brimstone has been recommended as a remedy 

 for it. 



Beetles {Order, Coleoptera). 



The Colorado Potato-Beetle (Doryphora decem-lineata, Say). — This, the 

 well-known Potato-Beetle (Fig. 12) needs no description. Under its normal con- 



Tig. 12. 



ditions, on the slopes of the Rocky Mountains, it fed upon the;wild^potato, Sola- 

 num rostratum. Access to the cultivated plant gave it that increase of vitality 

 and fecundity which has rendered it so formidable a foe to the gardener. 



