7 
BEAN BEETLE. 
and if so, how far ? When I wrote in question, I was informed that 
this insect in no way impaired the vitality of the germ; that it was, 
in fact, harmless, and did not reproduce itself in this climate; and, 
further, that contact with the cold earth soon destroyed it. 
“ Also that it was impossible to obtain Beans without a percentage 
of these insects, as the crop was harvested in the South of Spain, and 
during growth they introduced themselves into the pod.” 
In regard to the manner in which the maggot is introduced into 
the seed, the following appears to be the method of attack :—The 
beetles lay their eggs on the ovary of the blossom, or the pod in its 
youngest state, and from these eggs the maggot hatches, and eats its 
way into the seed. There the grub feeds and turns to chrysalis, and 
appears generally to pass the winter in this state, and to change to the 
beetle in the spring. Then it pushes out a round bit of the skin of 
the Bean, which has covered the entrance of its gallery, and comes 
out to start new attack. 
The common Bruchus granarius , which infests both Beans and 
Peas, is a common insect in this country, and we have direct evidence 
from experiment of John Curtis (see ‘ Farm Insects,’ p. 360) that 
Briichi were found by him on Beans which he had raised from foreign 
seed. He also mentions this “ Seed Beetle ” as a most destructive 
insect in Pea and Bean fields. 
With reference to the amount of injury caused to the germ ? The 
attack occasionally has been found to spread to this part, but the germ 
itself has been observed to be very seldom injured. The chief damage, 
as far as growth is concerned, is caused by the grub galleries removing 
a part of the substance of the seed, and the young plant being 
weakened by the absence of the full supply of nourishment which it 
should have received at the beginning of its growth. 
Autumn-sown Beans are more liable to be attacked than those 
which are spring-sown, because commonly the greater part of the 
beetles do not leave the Beans till the spring. Infested Beans may be 
known by having a little round depressed spot, as if the skin had been 
pressed down by the end of a knitting-pin. If this is noticeable on 
many Beans the sample may be considered to be still badly infested ; 
if instead there is a small hole, the beetle has gone, and the seed will 
therefore not contain anything to continue attack, but will be the 
worse by the amount eaten. 
As far as we know at present, the only security of the ordinary 
buyer lies in carefully examining a sample of the seed. When once 
he has seen the small horny-looking depressed spot on the skin of the 
Bean he will know it well in future, and be able to judge as to the 
state of his proposed purchase. With regard to importers, their best 
defence is that which I know to be used by one of our leading seed 
