FUMIGATION WITH HYDROCYANIC ACID GAS 353 



chamber. Sometimes pupation occurs in cracks or crevices in 

 the bin. 



Injury. This beetle, however, does not confine itself to grain 

 bins. It may be found hi store-rooms, granaries, pantries, and 

 bakeries. It seems to be practically omnivorous, and its small 

 size enables it to penetrate the smallest cracks. It is cosmopolitan 

 in its distribution. An important fact to be noted is that the larvae 

 may and do perforate paper bags and cardboard boxes which are 

 used as containers. 



The pest is easily killed by carbon bisulfid. 



The Cadelle or Bolting-Cloth Beetle. This interesting beetle 

 (Tenebroides mauritanicus Linn.) is fully one-third of an inch 

 long, nearly black, with depressed body. The larva, when full 

 grown, is three-fourths of an inch long and of a dull whitish color 

 with a dark brown head. The three thoracic segments are also 

 marked with brown. The last segment terminates in two horny 

 points (Fig. 361). 



Injury. Though partly predaceous, feeding on other mill 

 insects, this may be a serious pest in a flour mill. Both the larva 

 and the adult cut sacks, and the beetle is said to make holes in 

 bolting cloth. It may be found in accumulations in the bottom of 

 elevator boots and flour conveyors. It is a common pest, frequently 

 found in bags of flour in warehouses. While in search for food, 

 both larvae and adult devour any grain insects they come across. 



Control. For remedial measures, see measures of control 

 given for other mill insects. 



FUMIGATION WITH HYDROCYANIC ACID GAS FOR FLOUR MOTH 

 AND OTHER MILL INSECTS 



No process is absolutely perfect, and millers should not, par- 

 ticularly in the case of badly infested mills, expect immunity after 

 the first treatment. The inexpensiveness of the process, and the 

 fact that the gas at the strength used is non-explosive, and the 

 further fact that it in no way injures dry mill products, makes it 

 by far the most effective remedy available. Its poisonous qualities, 

 of themselves, make it safe only in the hands of those acquainted 

 with it, for the knowledge of the possibly fatal results from care- 

 less manipulation insures extreme care in its use. Under such 

 conditions, it is to be regarded as a safe agent. But it should be 

 borne in mind not only that the cyanide of itself is poisonous, 

 23 



