IJjG [December, 



markings usually dark are assimilated to tlie ground colour, or 

 where a pale ground colour is increased at the expense of dark 

 markings (e. g. when the red in the hind- wing of Arctia caja gains 

 ground at the expense of the black spots) is leucochroism. 



In determining whether a species has a tendency in either 

 direction, a certain allowance (how much, experience alone will show) 

 must be made for individual idiosyncracy in coloration. 



I will proceed with my analysis. 



Of the 480 (or thereabouts) Macro-Lepidoptera inhabiting Scotland 

 north of the Tay, the majority may be at once put aside as not 

 exhibiting sufficient variation for our purpose. Be it observed, 

 however, that when there is a tendency to variation, it is in the 

 majority of cases in the direction of a heightened (darker or more 

 brilliant), and not of a diminished, coloration. 



Another group, consisting of species more or less variable in 

 every locality, may also be dismissed with the same observation. In 

 it are included TcBniocampa, several species ; Larentia ccesiata ; 

 Crocallis elinquaria ; Hypsipetes, several species ; Oporahia dilutata ; 

 Cidaria russata and immanata, &c. 



The remaining species may then be divided as follows : — 



I. MELAifOCHEOIC. 



1. Species of which all the specimens, or a large majority, are 

 melanochroic — in short, melanochroic races. — Arctia menthastri (var. 

 ochracea) ; A. fuUginosa (var. horealis, Stdg.) ; Trichiura cratcegi 

 (approaching var. arice, Hb.) ; Orgyia fascelina (approaching var. 

 ohscura, Zett.) ; Scodiona helgiaria {\a.v. fdvillacearia, Hb.) ; Thera 

 juniperata {yiiv.scotica^ ; Mdanippe Jluctuata ; JVotodonfa dromedarius ; 



Gymatopliora duplaris ; Gortyna jiavago ; Apainea fibrosa ; Aplecta 

 occulta {Xote. The very north European form is pale). 



2. Species frequently melanochroic, but of which many indi- 

 viduals are not so. — Hepialus humuli (ab. hethlandica, Stdg.) ; 

 Odontopera hidentata ; PJiigalia jjilosaria; Aspilates strigillaria ; 

 Thera variata (ab. ohliterata) ; Melanthia rubiginata (ab. plujnbata, 

 Curtis) ; Cidaria sujfmnata (ab. piceata, Stph.) ; G. populata (ab. 

 musauaria, Frey.) ; Goremia ferriigata ; Bryophila perla ; 2^ylophasia 

 polyodon ; X.. rurea (ab. alopecurus, Esp. and ab. eombusta, Dup.) ; 

 Agrotis tritici ; Triplicena orbona (ab. Gurtisii, Newman) ; Noctua 

 ccanthographa ; Tceniocampa gracilis; Orthosia suspecta ; Epunda 

 vbninalis (ab. vbscura, Stdg.); Sadena adusta ; H. protea ; 



