16 VARIETIES OF NOCTIL33 



other NOCTU^J, the larvse having the number of feet normal in the 

 other groups, although the imagines are decidedly Plusia in appear- 

 ance etc. They (the imagines) are much less brilliantly marked 

 than the true Plusice, although retaining all the characteristics of the 

 family. There is a little variation in the amount of pale marbling in 

 tripartite, (urticce), otherwise there appears to be nothing particularly 

 noticeable. Guenee writes : " The perfect insects are exceptional in 

 this family, in that their wings are altogether without metallic spots 

 or lines ; as compensation, the ordinary stigmata are well marked and 

 surrounded by small upright scales which make them stand out still 

 more clearly. They vary little or not at all, although the larva of 

 each species has two well marked varieties, but this does not influence 

 the colour of the imagines " (< Noctuelles,' vol. vi., p. 320). Our two 

 British species are very different in general appearance, although it is 

 almost impossible to find a good structural point of distinction between 

 them. 



Abrostola, Och., triplasia, Linn. 



This species is very closely allied to the next (tripartite), and 

 apart from colour, it is very difficult to get a distinct point of 

 difference between them ; the basal line is, perhaps, more regularly 

 curved, and the elbowed line also more curved near where it meets 

 the inner margin in this species, but neither of these points is in- 

 fallible ; the spot between the stigmata is generally darker in 

 tripartita ; the small longitudinal marks near the apex ; the pale 

 stigmal mark which looks like an extension of the orbicular (so 

 characteristic in some of the Hadena) ; the raised scales on either side 

 of this mark and those round the basal line appear to be identical 

 in both species and show their very near relationship. I can find no 

 points of variation in this species except the slight sexual differences 

 in the antennge and abdomen. The type of this species is thus 

 described by Linnaeus : " Noctna spirilinguis, alis deflexis : superiori- 

 bus arcu duplici contrario maculisque tribus glaucis intermediis. 

 Crista thoracis reflexa, alta, pallida." " Alse superiores griseo-cinerese 

 arcu ferrugineo in ala antica et postica. Maculae tres interjectse glaucse, 

 quarum duae versus marginem lateralem " (' Syst. Naturae,' xth., 517; 

 ' Fauna Suec.,' 318). Of triplasia Guenee writes : " The description 

 of Linn is not at all satisfactory, but the citation of Roesel's figure 

 and the species which still exists in his (Linnaeus') collection remove 

 all doubt" (' Noctuelles,' vol. vi., p. 323). The glaucous coloration 

 mentioned in the Linntean description is highly suggestive of tripartita. 



Abrostola, Och., tripartita, Hufn., Rott. 



Distinct as is this species from the former in general appearance, 

 and easily as they can be separated, I fail to find a single point of 

 difference, apart from colour and general appearance, between them. 

 Unlike the former, this species varies considerably in ground colour 

 although it is always of some shade of purplish-red, sometimes very 

 pale, at others almost black. But the pale parts of the fore wings are 

 those which vary most. In Britain, these paler parts which are of a 

 greyish-ochreous coloration, generally extend as a more or less distinct 

 transverse band between the subterminal and angulated lines, and also 

 form a somewhat oval patch in the lower part of the basal area. In 



