EXPERIMENT STATION BULLETINS. 



207 



Fjg 4. Indian-meal moth, enlargerl, after Chitten- 

 den, Bureau of Ent., U. S. Depl. of Agr. 



also spin silken galleries all 

 through the elevators, spouts, 

 bolting machinery and everywhere 

 else, being especially troublesome 

 at the times when they are seek- 

 ing good quarters for spinning up. 

 Such quarters being found, they 

 spin tough, white cocoons, about 

 half an inch long or less, inside 

 of which the slender brown pupae 

 are formed. From these the moths 

 issue later and lay large quanti- 

 ties of eggs. 



The fact that only two months 

 or less are required for the creature to complete its life cycle, makes it 

 possible for it to multiply at an astonishing rate. The modern steam- 

 heated mill lends itself very nicely to the needs of this creature, which 

 is partial to warmth and darkness. 



The Mediterranean flour-moth resembles superficially another moth, 

 the Indian-meal moth {Plodia mterpunctella) which is scattered fairly 

 well over the country. The latter seems to prefer whole grain to flour 

 when there is a choice. It binds the kernels together by means of 



threads. The insect feeds 

 "~ on a great variety of 



dried vegetable products 

 and is apt to be found 

 in mills. The moths are 

 readily d i s t i n g u i sh- 

 ed from those of its 

 Mediterranean relative, 

 the front-wings being 

 light grey in color for 

 about one-third of the 

 distance and darker 

 brown for the re- 

 mainder. 



Fig. 5. Mediterranean Flour-moth, enlarged, after Chittenden, 

 Bureau of Knt.. U. S. Dept. of Agr. 



REMEDIES. 



Three methods suggest themselves for the control of this insect. First, 

 the substitution of metal for wood wherever possible. Metal spouts are 

 less likely to become clogged than those constructed of wood. They are 

 more easily kept clean and the moths do not like them so well. Second, 

 fumigation with carbon-bisulphide or with hydrocyanic-acid gas has been 

 recommended by several who have had to deal with the pest, but the first 

 named is extremely dangerous if breathed and extremely explosive if a 

 spark or fire in any form be brought to it. Heat, even in a considerably 

 less degree than that required for the combustion of wood, will ex- 

 plode the gas when mixed with air, as it is used in fumigating. It is 

 also quite likely to make trouble with the underwriters if any loss oc- 

 curs while it is in use at least. Hydrocyanic-acid gas is also extremely 



dangerous. 



A single breath of the gas of the strength used is sufficient 



