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



The duration of the pupa stage of the tobacco beetle at room tem- 

 peratures during the warmer months of the year in several localities 

 was as follows: At Key West, Fla., between May 13 and June 4, the 

 average time as shown by 10 records was days and the shortest 

 period 5 days. At Richmond, Va., the average of 11 records at room 

 temperatures was 7.8 days, the shortest period 6 days, and the longest 

 period 12 days. At Appomattox, Va., the average of 12 records ob- 

 tained during July and August was 8.1 days. During September 

 three records show pupal periods of 7, 8, and 9 days, respectively. 

 At Clarksville, Tenn., 3 records secured during April and May show 

 an average of 13.6 days, and 10 records during the period between 

 July 29 and October 1 an average of 7.8 days. At Tampa, Fla., 21 

 records during July show an average of approximate^ 7 days, and 

 6 records during October show an average of 8.1 days. 



THE ADULT. 



"When transformation to the adult stage has taken place the beetle 

 lies inactive within the pupal cell for a period of three to seven 

 days — usually about five days. After emergence it remains at rest 

 for a day or more on the outside of the cell ; the color of the beetle 

 gradually becomes darker, and the normal shade of brown is reached 

 about the time it has completed the resting period. The beetles are 

 comparatively soft immediately after transforming and do not attain 

 their final degree of hardness until they are ready to move away 

 from the pupal cell. 



The adults vary greatly in size. This undoubtedly is due to breed- 

 ing conditions, the quality or abundance of food obtained by the 

 insect while in the larva or feeding stage being the most important 

 factor. The females will average larger in size than the males and 

 they are also less active. In the vicinity of infested warehouses or 

 factories beetles frequently are found in surrounding dwellings, and 

 on several occasions were observed by the writer to fly from one 

 tobacco warehouse to another located on the opposite side of the 

 street. They avoid intense light, moving about most actively in sub- 

 dued light or in darkness. When in the dark they are attracted 

 toward subdued or artificial lights, and in tobacco warehouses often 

 may be found in great numbers at the windows in late afternoon, 

 the flight toward the windows being heaviest at sunset. Observa- 

 tions made at regular intervals throughout the night in a cigar fac- 

 tory showed that they were taken at a trap light at all hours of the 

 night. During the day the greater number will be found in secluded 

 places, such as crevices in the walls, or along the casings of windows, 

 and within the leaf tobacco. When at rest the head and thorax are 

 drawn downward (PI. III. fig. 1). They have a habit of feigning 



