affecting tlic Peas and Beans. 
417 
prevented,''* I have little more to add than to confirm Mr. 
Dickson's sensible observations, and the excellence of the remedy 
he proposed, which is now practised by all good cultivators, I 
believe. Late in the year I have seen the Colliers on the under 
side of French and scarlet bean-leaves, and this mild autumn 
they were observed upon the latter plants during the last week 
in October. Where the eggs are laid by the Aphides remains a 
mystery. It cannot be upon the Beans ; and as the apterous 
specimens are the precursors of the winged ones, as far as my 
observations have gone, they are not able to transport themselves 
in the first instance. Having once established themselves upon 
the bean-tops, their multiplication is no longer mysterious, for, 
being then viviparous, they breed at a rate which would b» in- 
credible, if it were not well attested. f As the Colliers are 
readily detected by their peculiar colour, often making the bean- 
stalks as black as soot, no one can find an excuse for neglecting 
to apply the remedy of removing the tops on the first indication 
of their presence. This, however, is not all that is required, for 
if they be not collected and burnt as the operator proceeds, the 
animals will soon crawl to the living plants, and those that have 
wings will fly away as the tops wither. Troublesome, if not 
expensive, as the method would be, I should recommend the 
employment of women and children to cut or pinch off the tops 
of the beans into skeps, heaping them up at one end or corner of 
the field and burning them as the work proceeds, or they might 
be thrown into a pit and trampled down with unslaked lime. 
The Aphides exhaust the plants by sucking the sap, so that 
when they abound, it is in vain to calculate upon a good crop, if 
they be not speedily arrested. The Lady-birds and their black 
larvae soon come to the aid of the farmer and destroy immense 
quantities, as well as the maggots of two-winged ^flies,§ and 
minute Ichneumonidce puncture the apterous females, as they do 
other plant-lice, II and where such agents are ascertained to be 
numerous, perhaps the reduction of the noxious animals may be 
safely intrusted to their instinct ; but I may here again notice 
the utility, and even necessity, of agriculturists being acquainted, 
to a certain extent at least, with the species of insects inhabiting 
their fields, for Mr. Middleton T[ acknowledges that he did not 
know whether the Lady-birds are the parents or the destroyers of 
the Black Aphides so injurious to the beans. This, however, 
* Dickson's Practical Agric, vol. ii. p. 597. 
t Vide Royal Agric. Jour., vol. iii. p. 51, 
% Coccinella, ib., p. 57, pi. C, f, 13—16. 
§ Scaeva, ib., p. 65, pi. C, f. 23—25. 
II Aphidius, &c., ib., p. 58, pi. C, f. 17, 18. 
^ Agriculture of Middlesex, p. 192. 
