30 Journal of the Department op Agriculture. 



colour, with a shining black head. It is full grown when it is about 

 three-tenths of an inch long, and ready to enter the soil to pupate. 

 It constructs a papery cocoon almost as long as its body, white in 

 colour, but usually appearing of the colour of the soil which clings to 

 it. 



The Adult. — The adult is a small black and white beetle, about 

 one- fourth inch long. The females are, as a rule, slightly larger than 

 the males, and can usually be reco^ized by their more distended 

 abdomens. The pale markings of the beetles aie not pure white ; they 

 are more or less a creamy colour on the M'ing cases and a light lemon 

 on the other part of the body. 



The most conspicuous character is found in the two pale stripes 

 on the wing cases. These run parallel down the back, bending out- 

 wards, before they reach the end, to join a narrow white margin on 

 the outside edge, and thus leaving the tips black. 



There are two black spots on either side of the thorax. Those 

 vary in size, and beetles are not uncommon which have the thorax 

 all black. The bases of the antennae and of the thighs, and certain 

 areas on the under-side of the body, are usually light coloured : but 

 specimens are found which have these all black. Some, again, have 

 pale wing cases, the black only showing slightly or not at all. 



Life-history and Habits. 



The Egg. — The eggs are laid standing up close together in 

 clusters, usually on the under-side of the leaves; but, in breeding 

 jars, eggs may be laid also on the upper surface, or on the stems, 

 fruit, or flowers, and sometimes on the sides of the jar. Up to as 

 many as 57 have been found together: but clusters of 10 to 30 are 

 more common than larger ones. Earely are eggs found singly. 



The beetles under observation in Durban in 1919 laid their last 

 eggs on the 10th of April. In 1920, beetles kept in jars on the north 

 side of the room, where the temperature was higher, continued active 

 much longer. On a visit paid to Piet Retief, 15th April, 1920. only 

 one full-grown larva could be found, and the conclusion was arrived 

 at that there the latest eggs deposited were laid about the end of 

 March. Some beetles were already in hiding; but others were still 

 present on the tobacco plants, no doubt recently emerged beetles feed- 

 ing preparatory to going into winter quarters. 



At Durban the period during which the beetles did not feed was 

 about four months. Eggs were found again from the 4th September, 

 and beetles were observed to be feeding two days before any eggs were 

 seen. 



The c^^ stage varies in Durban from four to seven days. At 

 the beginning of the season the period was seven days, and as the 

 season advanced it diminished, though not regularly, as at times it 

 somewhat lengthened again, till in the middle of summer tlie eggs 

 took only four or five days to hatch. Climatic conditions evidently 

 govern the length of the egg stage to a great extent; but otlier 

 factors are also concerned, as shown by the fact that eggs from 

 different beetles varied in their periods of incubation, a difference of 

 as much as two days having been observed in the times of hatching 

 of eggs laid by different females at the same time. "As will be pointed 

 out later the duration of the egg stage is of some practical interest. 



Some eggs do not hatch, and it was observed that certain beetles 



