LIFE-HISTORY OF THE LADY-BIRD BEETLE, 483 



when there was a great deal of wet and cloud}' weathei', a much 

 larger proportion was found on the more exposed surface, louring 

 the sunny part of July and August 1919 the pupfe were again 

 rarely found on the upper side. I have found no special orien- 

 tation of bipunctata pupae, such as is so striking in Anatis ocellaia, 

 which both on the trunk and needles of the pine norninlly faces 

 upwards. 



The average length of pupation in 1919 was 13 days, the mini- 

 mum 9 and the maximum 21. In 1919 the average was 17, the 

 minimum 3 and the maximum 28. In 1920 the average was 

 20 days, the minimum IG, and the maximum 22. Clausen and 

 Girault (10 «) both found the American average 6 days. The 

 very short period of three days was produced by placing the pupse 

 in a temperature of 101° F. 



e. 2'he Imagines. 



On emergence the imagines vary from palest yellow to orange. 

 Air and light usually produce the normal colour in a couple of 

 days, but at times the original orange may persist for weeks. At 

 certain seasons when bijyunctaia are emerging the majority 

 caught are of an oi'ange rather than the typical red colour. 

 This observation applies also to sejjtev^yunctata and variabilis. 

 The variations of colour so obvious in some collections are not 

 all true variations, but many nve probably due to the develop- 

 ment being still incomplete when the specimens were taken. 



Although the Lady-bird which emerges in August or Sep- 

 tember may live to the following June, a period of ten months, 

 its longevity during the summer is much shorter, the male 

 sometimes dying after a mating-period of three weeks, although 

 the female has lived two months after laying her eggs. Captivity 

 would no doubt greatly modify this character. 



The combined duration of incubation, larval life, and ];)upation 

 varied from 28 to 56 days. Tlie shortest period occurred during 

 the very hot weather subsequent to July 22, 1919. Burgess (1) 

 gives the complete pei'iod as 28 days in America. Avhere the 

 temperature would be very similar to that during this paiticular 

 period in 1919. 



Only a small pei-centage, 8 per cent, to 17 per cent., of the eggs 

 laid became ima,gines. Palmer's results wei'e better, as she 

 obtained from 13 per cent, to 25 per cent, of imagines. 



f. The Enemies of the Lady-hird. 



The colour of the Coccinellids is supposed to be protective, and 

 it is stated that they are not eaten by Insectivores. The yellow 

 exci'etion produced by both larvae and imagines is supposed to 

 protect them from preda.ceous enemies. The latter contention 

 appears to be partly based upon the fa.ct that the excretion is 

 disagreeable to Man both as regards taste and smell. Certainly 



