114 PRINCIPAL HOUSEHOLD INSECTS. 



cracked wheat, and patented foods, but likewise infests in the writer's 

 experience suck useful commodities as ginger, cayenne pepper, baking 

 powder, orris root, snuff, slippery elm, peanuts, peas, beans, and seeds 

 of various kinds that are kept long in store. It sometimes also attacks 

 cabinets of dried insects. 



As an instance of the nature of injury to flour in households may be 

 mentioned an experience recently reported, as it is one that may fall to 

 the lot of any housekeeper. The house had been closed for six weeks, 

 and on the return of the family the flour, which was kept in a large 

 wooden bucket with tightly fitting cover, and known to the trade as a 

 kanakin, was swarming with the larvsa and beetles of this species. 

 The damaged flour was removed and the bucket refilled, only to be-again 

 found with the insects at v ork in the fresh material. A personal exami- 

 nation showed that the insects, or enough of them to cause reinfestation, 

 had remained in the cracks of the bucket and in holes that they and 

 their larvae, or Silvanus surinamensis, which accompanied them, had 

 made in the soft wood. The bucket was again emptied and the pail 

 scalded, which had the effect of killing all the insects except a few 

 which were discovered to have escaped through holes which they had 

 made in the bottom. The pail had then to be painted on the bottom. 



Two reports have reached this office of injury by this species to bak- 

 ing powder. In one instance considerable damage had been done, 

 resulting in the loss of an entire consignment, necessitating its replace- 

 ment by the manufacturers, not to mention the annoyance to all parties 

 concerned. Customers were returning boxes of the powder almost as 

 soon as opened, on account of the presence of these beetles. The baking 

 powder, of which wheat flour was in this instance one of the ingredients, 

 is put up for sale in tight tin boxes, and so closely covered with paper 

 as to be practically air-tight; consequently the insects must have gained 

 entrance at the manufactory before the boxes were covered. 



The life history of this species is in brief as follows: The tiny, clear 

 white eggs are attached to some convenient surface in the cracks or on 

 the sides of the bag, barrel, or other receptacle in which the infested 

 substance is contained. These hatch into minute larvae, which feed for 

 a period, depending upon the temperature, and then transform to naked, 

 white pupae, which in due time change to beetles, which copulate soon 

 after transformation, and another generation enters upon its life round. 

 In this manner several broods are generated in the course of a year. 

 From observations conducted by the writer it has been learned that 

 this insect is capable in an exceptionally high temperature of under- 

 going its entire round of existence from egg to imago in thirty-six days. 

 The minimum period of incubation was not ascertained, but it may be 

 assumed as about six days. This, with six days for the pupal period, 

 gives twenty-four days as the shortest developmental period of the 

 larva. In cooler weather these periods last two or three times as long. 



