98 
Observations on the various Insects 
this country.* I regret that I have no experience regarding the 
transformations of this species, for all my attempts to rear it have 
been unsuccessful. In June, 1844, I carefully examined some 
barley in a box, which I had procured the previous autumn; 
numbers of the weevils had hatched, and many were lying dead, 
but I could find neither eg<rs, larvae^ nor pupa?. Leuwenhoek 
and Olivier, however, will supply this deficiency ; the former of 
these authors made many observations, which were published as 
long back as the year 1687, and the latter in the ' Encyclopedic 
Methodique.' It has been ascertained that after the weevils had 
paired, the female made a hole in the grain of wheat with her 
rostrum and deposited an egg in it, from whence hatched a little 
maggot, which during its growth ate out the entire contents, and 
then changed to a pupa in the empty husk, and eventually the 
perfect beetle ate its way out. The maggot is nearly a line long, 
very white, soft, and elongated ; the body is composed of pro- 
jecting and rounded segments, and is furnished with a large, 
horny, round, yellow head, with teeth or jaws to nibble the sub- 
stance of the grain. Only one maggot is found in each grain, as 
it is no more than is necessary to support it whilst it is in that 
state. t The pupa is a clear-white, and transparent, so that one 
can distinguish through the envelope the rostrum, antennae, and 
the other members of the insect. In this state, of course, it takes 
no nourishment, but lies dormant, and only shows svmptoms of 
life by moving its abdomen when it is disturbed. Eight or ten 
days after this metamorphosis the weevil bursts the filmy skin 
in which it is swathed, and pierces the epidermis of the grain to 
form an aperture and leave its prison. It is the maggots which 
make the greatest havoc amongst the corn, yet it is evident that 
the weevils also feed upon it, as they are sometimes found, of a 
dark colour, enclosed in the grains. 
It is well known that a certain degree of heat is necessary to 
invigorate these weevils and induce them to copulate. If the 
temperature be under 8° or 9° (50° or 52° Fahr.) the sexes have 
not sufficient energy to search for one another ; they live in a 
state of repose and even of torpor if it be cold, and are then in- 
capable of mischief. On the return of spring, especially in 
countries where that season is sufficiently favourable to raise the 
temperature to 10° (.54° Fahr.), the sexes pair; this happens 
about April in the south of France, and they go on propagating 
until the end of August : so that the destruction of grain is much 
more considerable in the southern than in the northern provinces. 
* It is very probable that in warm latitudes these organs may be fully 
developed. 
Encyclopedi' Methodique, vol. v. p. 488. 
