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MRS. O. A. 3IERRITT HAWKES ON THE 



are many easily procurable varieties, which, as far as is known, 

 are not regional. 



Palmer (21) worked for some time at Adcdia, but she liad only 

 a few varieties to deal with, as in America there occurs only the 

 " type" and three varieties, whilst in Europe there are more than 

 twenty-six named varieties. It would be impossible to get as 

 quick results here as in America, as two generations per annum 

 are the most one can obtain in England under natural conditions, 

 whereas Palmer succeeded in obtaining four and five during the 

 long American summer. Our erratic climate also makes the 

 food-supply (aphides) more uncertain tlian under more stable 

 climatic conditions. 



Coccinellids have been extensively studied in the United States, 

 as they are there recognised to be of considerable economic 

 importance ; but in England there has been little careful study 

 of their habits, their distribution, or the genetical and possibly 

 regional relations of the varieties which are so numerous in some 

 of the species. Donisthorpe (6) lins published the only complete 

 history of any species, Coccinella distincta. The following obser- 

 vations were made in the course of genetical experiments which 

 are still in progress. 



The varieties of Adalia have been determined chiefly by 

 Meissnei- and Schroder, who based their determination principally 

 upon the variations in the colour of tlie elytra, but neglected the 

 very considerable variations of the thorax. Schroder believes 

 that the varieties from pure red elytra at the one extreme to pure 

 black at the other a,re modifications of a scheme of seven spots 

 and a scutellar mark. This is an interesting matter of specu- 

 lation, but we do know that in Europe there are two principal 

 forms : (1 ) " type," in which the elytra are a reddish brown 

 with an approximately round black spot in the middle of each 

 elytron ; and (2) a black form with either two or three red spots 

 in each elytron : when two are present, an upper lateral and a 

 mid-dorsal, the variety is known as var. maculata ; when three 

 are present, an anal red spot being added to the above two, the 

 variety is named i^-pustidata. All other varieties, none of which 

 occur in large numbers, can probably be grouped about these two 

 main forms. 



The Red varieties are generally acknowledged to be commoner 

 than the Black, though very few accurate statistics have been 

 recorded. Meissner found 35*2 per cent. Black in Summerfeld 

 and 42*3 in Potsdam. In Staffordshire and Warwickshire I 

 found 29 per cent. Black in 1918, 25 per cent, in 1919. In 1920 

 I found 2*75 per cent. Black at Crouch Hill, London, N., 42*7 per 

 cent. Black on hops at Bishop's Frome, Herefordshire, 11 '7 per 

 cent, at Enville, Staffordshire, and, very much to my surprise, 

 78"5 per cent. Black in the Edgbaston district of Birmingham. 

 Further observations will show whether localities are characterised 

 by certain varieties or whether the prevalent varieties vary from 

 time to time, If the varieties reniain tlie same, will it mean tliat 



