THE TOBACCO BEETLE. 49 
TABLE VII.—Hffect of exposure of stages of the tobacco beetle (Lasioderma ser- 
ricorne) to ultra-violet rays. Experiments at Clarksville, Tenn., 1916. 
Exposure. Results. 
cs Dis- 
Stage of |Ageof] Cur- olt- | tance 
Date. F y Eggs on upper 
Insect. | eggs.|rent.| age. Hou Time.’ ate ofleaf; | Eggsonunder-| Eggs under 
Bi E une exposure side of leaf. glass cover. 
y direct. 
vapor 
are. 
| 
i | 
1916. Days.|Amp Inches. | Ain. 
Jill PAD MN IDES 68 a 1 | 3.3) 66-67 8 4,| None hatched| All hatched...) All hatched. 
JNTERS We ee ese Gower: 1-2} 3.3] 66-67 068 Ble cae GOL eats lene ee doe. oeecee Do. 
IDO Ses ldisoed does 4-5 | 3.3] 66-67 8 4 | Nearly all | Hatching nor-| Hatching 
hatched. mal. normal. 
drwy AO |ecoos doe. 3 8 70-75 Go 5 | None hatched|..... dO sciseese | Do. 
Uwhy Pl essde Gosease 2) 3.3 | 66-67 8 Qe sees Come eee dokess sees Do. 
July 24 |..... donee 4) 3 70-75 8 AD kee GOs Sse eee Goze saeces Do. 
July 20 Allstages..) 1-3 | 3.3] 66-67 Ted 8 | Exposed directly to rays. Eggs sterilized. 
o effect apparent on other stages. 
July 24) Adultsand) 2-3] 3 70-75 8 5 | Exposed directly to the rays. Eggs steril- 
eggs. ized. No apparent effect on adults. Fer- 
tile eggs deposited after exposure. 
TRAPPING. 
ATTRACTION :‘TO LEAF TOBACCO. 
In cigar factories it has often been noticed that the adult beetles 
collect on hands of leaf tobacco suspended for the purpose of ascer- 
taining the humidity. Eggs in large numbers frequently can be 
found on the leaves, and in the rooms where cigars are made or 
handled young larve from these eggs may easily find their way to 
the cigars. Numerous experiments were made by liberating large 
numbers of the beetles in a closed room in which hands of leaf to- 
bacco had been suspended about the walls. It was found that a large 
proportion of the beetles collected on the tobacco. This habit of the 
insect suggests the possibility, where conditions permit, of trapping 
the adults in this manner. The tobacco could be collected at frequent 
intervals and the eggs and beetles killed by heating or fumigating 
the leaves, and then replaced; thus, instead of being a source of in- 
festation, this tobacco would to a large extent protect the cigars or 
other material in the room. The method is said to have been tested 
in a cigar factory in the Philppines and to have shown excellent 
results (78). 
TRAP LIGHTS. 
The movement of adults toward light has been discussed under | 
* Phototropism ” (p.25). Specially constructed trap lights may often 
be used to advantage in factories or warehouses, and a large number of 
the beetles destroyed. A very efficient trap can be made quickly and 
easily by pinning together sheets of sticky fly paper in the form of 
a cylinder and suspending it around an electric light. The trap is 
75257°—19—Bull. 737-4 
