132 THE ENTOMOLOGIST. 



black margin at all — and these were taken in a damp and 

 gloomy copse. On the other hand, plants which are stunted 

 in their growth — as in the neighbourhood of manufactories, 

 ill-watered districts and hill-tops — seem to produce dark 

 varieties, as was partly noticed in the ' Entomologist' for 

 April (Entom. x. 93). Food in a semi-withered or dry con- 

 dition produces dark moths of small size ; for Amphydasis 

 helularia thus fed becomes in a few generations completely 

 black ; and by the same means the proportion of black to 

 white in Abraxas grossulariata, and of brown and black to 

 white and red in Chelonia caja^ is largely increased. Chalk 

 districts seem, as a rule, to be inhabited by insects of a 

 bright, light colour, such as Lyccena Corydon, L. Adonis, 

 and numbers of Geotnetrce, in which a clear chalky white 

 takes a prominent place. Excessive cold is productive of a 

 bleached appearance in all branches of the animal world. 

 Lastly, plants possessed of resinous or other strong vegetable 

 properties may be said in general to produce dark brown 

 moths — Boarmia abieiaria, &c., Thera variata, T. jiini- 

 perata, T. simulata, are a few instances out of many. These 

 facts seem to point to four conclusions: — (1) A large per- 

 centage of water in the tissues of the food-plant lends to 

 produce a large pale variety ; while small, dark specimens 

 result from dry and stunted food. (2) Resinous and other 

 strong vegetable properties produce distinct brown markings. 

 (3) Chalk soils produce a chalky while or bright colour in 

 insects : conversely we would expect rich loamy soils to be 

 haunted by deeply-coloured moths. (4) A cold climate, or 

 the gloom of damp dark woods, causes a bleached appearance 

 and general absence of distinct markings. Hence a bright 

 and hot sun-light may be supposed to produce bright 

 distinct colours. Experiments in rearing insects by various 

 collectors during the coming season might — by the unilormity 

 of their results or otherwise — fairly settle this much-vexed 

 question of melanism, which is so obviously connected with 

 development of species as to become highly important. 



St. Leonard's, April, 1877. 



