16 BULLETIN 737, U. S. DEPARTMENT OF AGRICULTURE. 



onic larva lies with the head at the rough end, and when development 

 is complete it eats its way through the shell in this position. Larva) 



hatching in glass vials at the laboratory were observed to consume 

 (he eggshells almost completely when food was not provided. In 

 rearing the insects for experimental work the young larvae were often 

 observed to live without food for periods of from 5 to 10 days. On 

 emerging from the egg they are much more active than at other stages 

 of growth and are capable of crawling a considerable distance in 

 search of suitable food. Their activity at this stage accounts for the 

 rather strange infestation of tobacco products, as the extremely 

 minute worms readily enter very small openings in the boxes or con- 

 tainers. On hatching the larva} are semitransparent, gradually as- 

 suming a whitish or creamy color as they become more fully grown. 

 The food within the alimentary canal, seen through the skin, gives 

 them a dark or dirt} 7 color, which, varies with the amount of food 

 present. When feeding on tobacco the fine particles of dust adhering 

 to the minute hairs of the larvae give them a brownish appearance, 

 which is more noticeable in the last instar. The larva? appear more 

 robust, deeply wrinkled, and grublike as they become more fully 

 grown. The young larva lies and crawls extended to full length; 

 the older larvae usually assume a curved position and are not so active 

 as those newly hatched. At all stages of growth they are negatively 

 phototropic, and when exposed to light disappear within the food 

 substances as quickly as possible. 



Larvae of all ages are capable of crawling for a short distance and 

 often migrate from infested to uninfested material. This habit often 

 accounts for the quick appearance of injury in freshly made cigars. 

 Partly grown larvae have been found on the cigarmakers' tables and 

 on the pickers' tables. They easily enter the open ends of the cigars 

 that are being handled, and in a ver} 7 short time their work can be 

 noticed in the bundle or box of cigars. In a box of injured cigars 

 examined, the work of a single larva was traced through four cigars. 

 In another instance, in a box of sliced plug smoking tobacco, a single 

 larva had cut a furrow in the tobacco for almost the entire distance 

 across the top of the slices between the oiled paper covering and the 

 tobacco. 



It has been observed by leaf -tobacco dealers that a crop of Cuban 

 tobacco which remains raw and does not cure quickly is apt to be 

 damaged more by the beetle than the same type of tobacco which 

 matures and cures properly. Under laboratory conditions a test was 

 made at Richmond, Va.. in 1014, with several types of leaf tobacco 

 which confirms observations made in warehouses and. factories. 

 Similar quantities of different kinds of tobacco were closely packed 

 in a tight container and several thousand eggs of the beetle scattered 



