4 



LIFE-IIISTOllY OF THE LADY-BIRD BEETLE. 479 



the Jarval or pupal stages. Tliis phenomenon is not clue to con- 

 finement or lack of foorl. as it takes place in the presence of 

 abundant food and in normal natural conditions. One can easily 

 watch what appears to be a form of Ooccinellid degeneiacy among 

 the larvjB wliich frequent red and black currant bushes. I have 

 seen adult bipunctata and septempunctata eat their own eggs in 

 boxes and on the trunks of trees, but never eat either larvae or 

 pupfe. This habit was also observed (6) in C. distincta in con- 

 tinement. Palmer has, however, observed the imagines eating 

 larva? when there was no other food in the cao'es. On one 



o 



occasion I watched a hipunctaia eat tlie abdomen of a small fly 

 caught in a spider's web. After a period of experimental star- 

 vation, two Adalia bipunctata feasted upon a small weak relation. 

 Cannibalism has also been noticed by Palmer, Johnson, Burgess, 

 etc. 



On hatching, the almost colourless larvae remain clinging to the 

 empty egg-sliells, part (never all) of which forms their first meal. 

 They next fall upon one another. This same early habit of 

 cannibalism also occurs in Epdachna (27), the vegetarian Lady- 

 bird. If by cha.nce an egg lags behind the others, it never 

 hatches, for it is eaten by a lai-va which was born a little earlier. 

 The larvae remain on the egg-mass until fully coloured, and then 

 suddenly and simultaneously disperse. Approximately a quarter 

 of the larvse are eaten before this dispersal. 



During the first instar there is great mortality, partly owing 

 to lack of sufiiciently small apliis and partly to cannibalism. The 

 young larvfc do best in small boxes, as they seem inca])able of 

 wandering far at this stage to find food, which, I believe, is 

 chiefly obtained by good luck and persistent wandering. As 

 early as possible the larva? were isolated in separate boxes, but I 

 was inclined to think cannibalism in the early stages a physio- 

 logically highly suitable diet, and, with this in view, I fed the 

 bipuRctata with small larvje of other S[)ecies. This practice was 

 not, however, always successful, as sometimes the eater became 

 the eaten. Partially successful attempts were made to feed the 

 larvfe on cooked and raw hen's egg. Ooccinellid eggs were 

 always eaten when put in the boxes, but this is not a suitable 

 proceeding in the early instars, as an odd egg may escape and 

 liatch. During 1918, 21 of 22 families were reduced to one, as 

 the full significance of cannibalism was not then recognised. 



It is interesting to consider the intermittent competition 

 between larvre of the same batch of eggs. It is not the larva 

 which first starts in the race which necessarily first reaches the 

 winning-post. It may be the first to reach the end of the first 

 instar, but during the short quiescent period which precedes 

 ecdysis, it becomes a defenceless prey to those who have lagged 

 behind. This special danger recui's at the end of each of the four 

 instars. 



The method of attacking the pupa is always the same, the 

 larva beginning on the ventral side near the anal pbint of 

 attachment and eating its way upwards and forwards, half 



