120 



relations existing between leguminous plants and the nitrifying 

 bacteria. 



Mr, Main referred to the farmers' custom of growing leguminous 

 plants and ploughing the crop into the soil in order to enrich it for 

 the main crop to be grown following. 



Mr. Bunnett noted that the roots of the bean were poisonous. 



Mr. Step said that the lupine was a common crop plant in South 

 Europe for the same reason. The Scarlet Kunner was naturally a 

 perennial, though grown in this country as an annual owing to its 

 failure to survive our winter. 



Mr. Tonge exhibited his series of D. mendica. 



Mr. R. Adkin then read his paper, " IHacrisia mendica its History 

 and its Varieties." (See p. 48.) 



In the discussion which ensued Mr. Mera referred to the difficulty 

 of carrying on a race in captivity after the second or third genera- 

 tion. Mr. Newman had bred it in large quantities generation after 

 generation, but that was on the growing plant in an outdoor cage, 

 where in fact, after eight years, he found it difficult to get rid of. 

 He reported that he had obtained a sooty black female from Box 

 Hill. 



Dr. Cockayne contributed the following remarks : — " The experi- 

 ments of Onslow have shown that the pale cream coloured form of 

 male is dominant to the dark brown one, but that there are many 

 factors for lightness and darkness involved. From my crosses of a 

 very pale form of Irish male and English female I obtained in the 

 second generation males as pale as the palest Irish ones. On the 

 other hand, a correspondent in Dublin by interbreeding Irish 

 )iiendica gradually got darker males, until he had some as dark, or 

 nearly as dark, as the average English males. No doubt he was 

 extracting recessives. Irish males vary very much in colour; many 

 are darker than the first cross between pale Irish and English 

 viendica, and a few are as dark as the paler English ones. 



"The name ruKtica is unfortunate in that it covers a number of 

 forms bearing different factors for colour and not a genetically 

 homogeneous race, but since we cannot distinguish these different 

 forms by their superficial appearance, it is convenient to retain it 

 for the pale Irish and Eastern geographical races. The various 

 kinds of spotting are very interesting, and I am sure these are due 

 to a number of Mendelian factors, although my own data are in- 

 sufficient to prove it definitely. The insect is unsuitable for exten- 

 sive breeding experiments owing to its susceptibility to a disease, 



