54 



The Xatuealist. 



lariata. To these I might add Hejnalus lujmlinus, Chelonia plantaginis, 

 Arctia luhricipeda. Bombyx querous, Fidonia atomaria, Lomaipilis mar- 

 gbiata. Syhernia defoliaria, Gidaria immanata and russata^ Apamea 

 oculea, Tceniocampa viidabills and opima, tfec. Some vary regularly and 

 constantly in -jne given way, either to dark or light, but generally to 

 dark, — as A. Pajjliia var. Valezma, T. biundularia var. Belamerensis, 

 A. avermta, banded form, Hyhertiia leucopliearia var. nigricaria^ and the 

 dark-bordered form we get generally, ; H. progemmaria and defoliaria, 

 a dark nnicolorous form of each of which we get here : Staurop^isfagi, 

 Arctia fuliginom, dark Scotch form; A. ?'umicis, ybly. salicis, X. rurea, 

 var. combu-sta ; X polyodo/i, dark form : T. orboua, var. Curtisii, &c. 

 C>r to light, as Colias Edusa, var. Helice, C. Hyale, pale form of female, 

 and pale females of all other species of the genus Colias ; P. plilo&as, 

 var. Schmidtii, Z,fiUpe}idiilce,TdiT. hippocrepidi-s, and tri/oliiy yellow var. ; 

 LitJiosia griseola var. stramineola, C. plantaginls, var. Jiospita, XantJiia 

 cerago, var. gilmgo, Haw., &c. 



Some varieties seem to be influenced by latitudinal or altitudinal 

 distribution : var. Hospita and var. Merope^ for instance, are con- 

 sidered alpine forms, while the dark Polyodon, Duplaris, Occulta, and 

 Orboiia are looked upon as northern forms, and vars. Valezhia, and 

 Dinie/isis- as southern forms. 



Out of a list of 79 species of British macro-lepidoptera, which I 

 made out as being subject to produce varieties, 37 had a tendency to 

 vary from light to dark, while only 18 had the opposite tendency to 

 vary from dark to light, and 24 had a tendency to vary in both 

 directions. Of the latter (those which varied in both directions) 14 

 had a majority of specimens for the dark, five had a majority for the 

 light, and five varied in both directions in about an equal degree. 

 Of those species Laving a tendency to produce varieties darker than 

 the type, 24 had produced dark varieties which may be said to be 

 persistent and for the most part named, while among the light varie- 

 ties only 11 had become established. Amongst the dark varieties, 

 some, as Occulta., Duplaris, Belgiaria, Fuliginosa, &c., seem confined, if 

 not to Scotland, to the northern portion of our island, which seems to 

 go against the generally admitted rule that cold is productive of a 

 bleached appearance ; hence some other cause must be assigned which 

 acts stronger than the bleaching influence of the cold in these cases. 

 A striking instance is found in V. urticce, where we find it in the 

 south {Iclmma) lighter than the type, and in the north {Pylaris} 

 darker than the type, but these are exceptions to the general rule 

 which under our present state of knowledge we cannot account for. 



