ON THE LIFE-HISTORY OF THE LADY-BIRD BEETLE. 



475 



30. Observations on the Life-Hisfory, Biology, and Genetics 

 of the Lady-bird Beetle, Adalia bipunctata (Mulsant). 

 By Onera a. Mkrritt Hawkes, M.Sc. (Birm.), 

 B.8c.(Lond.)*. 



[Received July 3, 1920: Read November 2, 1920.] 

 Contents. 



Page 



1. Introduction 475 



2. The Pood and Feeding of J.c?a7/r( S/pimci^afa 477 



3. Notes on the Life-History 480 



a. Mating 480 



h. The Eggs 481 



c. The Larva; 482 



d. The Papa? , 482 



e. The Imagines 483 



/. The Enemies of the Lady-bird 483 



g. Hibernation 484 



4. The Genetical Relations of the Varieties 485 



5. Summary 488 



1. Introduction. 



During three years of breeding pure and hybrid silkworms 

 {Philosamia), I have been increasingly impressed by the apparent 

 reasonableness of what would be regarded as fluctuating varieties ; 

 and by reasonableness, I mean a genetic relation between the 

 variations of the parents and those of the offspring. To under- 

 stand such variations, what appears to be needed is a large 

 number of exhaustive studies of normally occurring varieties in 

 animals untouched by Man. Insects present a large number of 

 variations, but little or nothing is known of their inheritance. 

 The Japanese have made extensive studies of silkworms (largely 

 domesticated), and in America, Roswell Johnson (13) has made a 

 wide study of Hippodamia, as a result of which he has been able 

 to make the following important statement (13): — "Every variety 

 or noticeable variation of HippodciDiia that has been tested is 

 inheritable in some degree." Miriam Palmer (21, 21a) has also 

 made successful studies of the American varieties of Adalia and 

 other Coccinellids. Meissner (19, 20) and Schroder (23), in 

 Germany, have made a small number of breeding experiments 

 with some of the varieties of Adalia bipunctata. 



Work of this kind would have the added advantage that in 

 some cases the sciences of genetics and classification would be 

 able to go hand in hand, instead of, as is too usual, being mere 

 bowing acquaintances. 



Adalia is highly suitable for work of this character, as there 



* Communicated bv E. Green, F.Z..S., P.E.S. 



32* 



