LTFE-HISTOHY OF THE LADY-RTItl) BEETLE 485 



September 19] 1). Early in li)2U lie visited this place, and found 

 large numbers of tlie insects lying massed upon one aiif^tl cr in 

 Ihe cracks between the bricks Avhere theie was practically no 

 shelter. The Lady-birds were on all sides of the cliimney. 



In September 1919 large numlteis of KoptpmiynncUda were 

 repoi'ted from various parts of Enghind, bnt in Staftbrdshire 

 there were at the same time large numbt^rs of hi%nmctata and 

 6'. l\-punctata, wbicli, on account of their small size, weie much 

 less obvious. This abundance was entirely accounted for by the 

 weather-conditions. Early in Auijust there had been a. period 

 of warm fine weather during -wliich aphis and Coccinellid larva? 

 flourished : this was succeeded by a, wet, cold pei'iod, which no 

 doubt I'eta.rded the pupae; but when a second period of liot 

 weather supervened, the retai'ded pupae responded, as my breeding 

 experiments show they will do, and simultaneously, instead of 

 over a protracted period, tlieadidts appeared. 



4. The Geneiical Relations of the Varieties. 



Matings were made during the summers of 1918 and 1919. 

 During the first year, only 22 of the 57 fertile matings produced 

 a complete generation, the family in eacli case being reduced to 

 one imago. In 1919, 23 complete generations were produced 

 from 35 matings. 



Eleven of these successful matings were Red x Red, and with 

 tlie exception of one. Mating 82, produced only Red oftspring, 

 among which there occurred small variations from their parents 

 and from " type." The Red bi'ed true, producing none of the 

 Black variety. 



The exceptional mating (32) consisted of two Reds taken \'.hen 

 mating. The female laid one small batch of eggs (7), from which 

 two Black imagines were produced. Clearly the female was at 

 the end of her productive period, and liad prol)ab1y mated with a 

 Black before she was caught. 



Six matings of Black x Black were made, five of wliich pro- 

 diiced both Red and Black imagines, a j^henomenon quite 

 different from the Red x Red matings ; but as it was not possible 

 to guarantee that the females bad not had pai-tners pi-evious to 

 the scheduled one, it cannot at present be deduced that the 

 genetic constitution of the Black as regards the puritv of the 

 genes is difl:erent from that of the Red. 



The sixth mating (24), which produced only Blacks, was as 

 follows : — 6 var. 4-maculata X ^ 4-macxdata pi'oduced five 

 4-maculata and one 6-pustulata. The female had certainly had 

 no previous mate. 



The five matings of Black x Black produced 8 Blacks and 

 4 Reds. It must be noted that these Reds were all variations 

 from "Type" and not exactly like the Red parent. The pioblem 

 therefore arises — are these vaiiations lietei'ozygous forms with ay 

 intermediate appearance ? Similar varieties have, however, been 



