34 Journal of the Department of Agriculture. 



20th of July. The eggs in the cold weather took up to nine days 

 to hatch, the larvae up to five days to the first moult, up to five for 

 the second moult, four days to the third moult, eight more days to the 

 time of entering the soil, and twenty-eight days before the adult 

 emerged. The conditions were abnormal ; but the observations are 

 interesting as showing the maximum periods for the different stages 

 so far recorded. 



Food-plants. 



Besides on tobacco, the slugs have been observed either in the 

 field or in the laboratory to feed on Cape gooseberry (Phy sails peru- 

 viana), the wild Cape gooseberry {Nicandva jyhysaloicles), Vhysalis 

 TniniTna, Phy sails lobata, and on other species of Pixy salts, and thorn- 

 apple, or stinkblaar {Datura stramonium) and D. tatula; while 

 Salpichroa rliomhoidea is reported from the Argentine as a food-plant. 

 All these are solanaceous plants, and none of them known as natives 

 of South Africa. 



The insect seems to be somewhat restricted in its range of food- 

 plants, as not all solanaceous plants can serve as food. Tomato, 

 potato, capsicum, brinjal {Solanum melongena), inkberry [Cestruin 

 aculeata), Solanum aculeatissimum, S. auriculatum, and two other 

 solanums were tried as food-plants and found not suitable. A few 

 plants, not belonging to the solanaceae, including sweet potato and 

 lucerne, were also tried, and were refused. 



However, speaking of the insect at Cedara, Mr. S. H. Skaife, 

 Lecturer in Entomology there, says: ''The beetle occurs on potatoes, 

 although the damage it does is slight. I notice that in the potato 

 fields Datura stramonium is almost defoliated, whilst the surrounding 

 potatoes are hardly touched." 



Some food-plants seem to be much preferred to others. In Piet 

 Retief serious damage to tobacco is being done, but Mr. Faure found 

 Datura and Phy sails growing close to infested tobacco, practically 

 free, while Nicatndra physaloides was more infested than the other 

 two weeds growing in the same garden. 



The adults appear to have the same food-plants as the larvae, 

 but they are not so voracious and do not do so much damage. 



Means of Distribution. 



The beetle must have been artificially transpoited from South 

 America, but we do not yet know enough of its distribution in South 

 Africa to say whether its range has been extended by natural spread 

 or whether it has also been carried by traffic from one place to 

 another. That the beetles will enter mine-props, bales of wattle bark, 

 and tobacco, or other produce, is quite likely. The greatest danger 

 would appear to lie in bales of tobacco. Beetles emerging in a 

 tobacco-shed and finding there tobacco still green, would feed and 

 hibernate in the shed, and possibly enter the tobacco bales. Beetles 

 have been found in bales brought from farms into Piet Relief. The 

 greatest danger of transporting beetles is no doubt during the time 

 they aie liibernating. In the summer, it has been observed, 

 the beetles may also enter a resting stage for as long as two M-eeks, 

 but such resting periods are exceptional; and, further, tobacco bales 

 then shipped would most likely be from the previous season's crop. 

 Hibernating beetles would have gone from them, and no fresh beetles 

 would vet have emerged in the sheds. 



