176 INDIRECT INJURIES CAUSED BY INSECTS. 



are more kinds than one, seldom multiply so fast as to be 

 very noxious to those plants ; while those which attack 

 pulse spread so rapidly, and take such entire possession, 

 that the crop is greatly injured, and sometimes destroyed 

 by them. This was the case with respect to peas in the 

 year 1810, when the produce was not much more than the 

 seed sown ; and many farmers turned their swine into 

 their pea- fields, not thinking them worth harvesting. The 

 damage in this instance was caused solely by the Aphis, 

 and was universal throughout the kingdom, so that a suf- 

 ficient supply for the navy could not be obtained. The 

 earlier peas are sown, the better chance they stand of 

 escaping, at least in part, the effects of this vegetable 

 Phthiriasis. Beans are also often great sufferers from 

 another species of plant-louse, in some districts from its 

 black colour called the Collier, which begins at the top 

 of the plant, and so keeps multiplying downwards. The 

 best remedy in this case, which also tends to set the beans 

 well, and improves both their quality and quantity, is to 

 top them as soon as the Aphides begin to appear, and 

 carrying away the tops to burn or bury them. In a late 

 stage of growth great havoc is often made in peas by the 

 grub of a small beetle (Bruchus granarius), which will 

 sometimes lay an egg in every pea of a pod, and thus 

 destroy it. Something similar I have been told (I sus- 

 pect it is a short-snouted weevil) occasionally injures 

 beans. In this country, however, the mischief caused by 

 the Bruchus is seldom very serious ; but in North Ame- 

 rica another species (B. Pisi) is most alarmingly destruc- 

 tive, its ravages being at one time so universal as to put 

 an end in some places to the cultivation of that favourite 

 pulse. No wonder then that Kalm should have been 



