c 
THE BEAN MAGGOT. 
upwards, that the empty pupa cases, the pupa;, and the maggots 
are successively met with. Nearly a hundred individuals in 
■different stages of growth maybe detected in a single bean-plant, 
though but lOin. or less in extreme height. 
The fly, which is quite a small though conspicuous insect, 
with its wings directed obliquely backwards, is black, but its eyes 
present beautiful copper-coloured and green reflections, and its 
wings have an opalescent glimmer when viewed in certain posi- 
tions. It deposits its eggs in the first instance upon or within 
the tissue of the bean plant when the latter is still quite young, 
perhaps even before the first true leaves liave expanded ; and 
the injury is then inflicted in the stem immediately above the 
surface of the ground, the maggots feeding both upwards and 
downwards, just beneath the epidermis. Having attained their 
full dimensions they pupate in situ: and the flies as they emerge 
deposit their eggs higher upon the plant at the insertion of a 
stem leaf or flower-stalk, the maggots of the second generation 
still feeding upwards, just beneath the skin. The pest is assist- 
ed in its progress through the plant-tissue by a large and stout 
hook-shaped toothed apparatus in front of the mouth, and by 
rows of sharp papilla just behind the head, and at the joints 
separating each body segment. As a rule the maggots are not 
met with within the central hollow of the stem itself, except 
when they can gain access to it, for pupating, either at the dead 
portion at the “collar” of the plant, or where a decayed spot 
occurs through the falling-off' of a branch. The pupge, however, 
generally occur, as do the maggots, just beneath the epidermis. 
The maggot attains its full size within a few days, and the fly 
emerges from its chrysalis (puparium) after the lapse of ten days 
— or less, if the weather is warm. 
The technical description of the pest in its different phases 
IS postponed, but the symptoms of its presence and the facts of 
its life history are enlarged upon, since it is by these that its 
presence may be recognised, and so steps be taken for its extir- 
pation. Probably it will everywhere prove equally destructive 
at first to dwarf French beans, and to these especially, with a 
possible tendency to attack the horse gram. It has been sug- 
gested that this Oscinis, as being partial to leguminous plants, 
