GENUS CALANDRA. 103 



bears strict relation to a certain degree of heat : if it be under 50° Fahr., it is insufficient 

 to afford them force or vigor to desire copulation : if the weather be cold, they remain in 

 a lethargic state, and are incapable jDf injury ; if warm, they pair very frequently. The 

 deposition of eggs commences sooner or later, according to the season or climate : the 

 female deposits them in all months, when the temperature is up to a suitable degree, 

 ceasing to lay when the mornings grow cold. 



1 From the moment of pairing to the appearing of the perfect calandra, there is an in- 

 terval of forty or forty-five days. By this Ave may see that a year must produce many 

 generations, which multiply still more in very hot climates. According to a table for the 

 calculation of their increase, it results that the sum total of each generation added to- 

 gether is 6045, proceeding from a single pair during five months, from the end of April 

 until the middle of September, while the mercury continues above 65° Fahr. We are 

 therefore no longer astonished if enormous heaps of grain are destroyed by these insects. 

 The injured kernels may be known by a very simple process : if several handfuls of the 

 grain be thrown into water, those will swim upon the surface which have been robbed of 

 their farinaceous substance by the destroyer. 



' It is not upon the surface of corn heaps, but some inches beneath, that we find these 

 insects ; and there, unless dislodged by shaking with a shovel or sieve, they will remain 

 so long as the weather continues warm, living, pairing, and depositing their eggs. When 

 the mornings begin to freshen, all, both young and old, retire to clefts of walls and the 

 flaws of wood and floors. They are sometimes found behind tapestry, chimnies, in fine 

 every place affording a warm retreat. 



' It has been supposed seriously that these insects remain lethargic during the whole 

 winter, and return in spring to their abandoned grain-heaps, recommencing the deposition 

 of their eggs ; the cold incapacitating them for the exercise of the functions necessary for 

 the multiplication and preservation of their species. Based upon the knowledge of this 

 fact, is the substitution of cold as a remedy. It has therefore been proposed to have a 

 ventilator, the effect of which would be to keep in a granary a degree of air sufficiently 

 cold to reduce these insects to the above lethargic state. A general and constant rule among 

 insects is, that those which have paired perish shortly after, and do not pass the winter 

 except in the egg or larva state. It is doubtless rare that even those which have not been 

 exhausted by fulfilling the intentions of nature, can survive the winter rigors. Mr. Gay- 

 lord, however, in his prize essay published in the Society's Transactions for the year 1843, 

 says, of some specimens of wheat that he had received from the Patent Office, in which he 

 found weevils, that "selecting some pure flint wheat kernels, all perfectly sound, we 

 enclosed a dozen of these weevils with the wheat in a large phial to prevent their escape. 

 The phial was wrapped in paper, and placed where it would not be disturbed except for 

 examination. Opening it occasionally for more than a year and a half, I found my weevils, 

 with the exception of one or two, all living, and appearing to enjoy themselves much on 



