IN THE BRITISH ISLANDS. 15 



marks, or signs of gold or silver, often equalling the best polished 

 metal. They have nothing particular in their manners, and fly in the 

 evening with the greatest swiftness ; but I have noticed in my 

 1 Essai ' the singular hardness of their abdomen which is more sonorous 

 and more hollow, so to speak, than that of other NOGTD-SJ. I do not 

 know whether anatomists will one day be able to explain, by an actual 

 difference in the tissue, this exceptional organisation, or whether it will 

 be necessary to class it with unexplained illusions" (I.e. pp. 319-320). 

 Guenee also adds : " The Plusidce are found in all parts of the world, 

 and their beauty has attracted the attention of authors, so that a certain 

 number of these species is known even among the exotics " (1. c. p. 

 320). Our British species are included in the two genera Abrostola 

 and Plusia, and are, in most instances, very beautiful, although not 

 exhibiting any striking variation in any of the species, except in the 

 peculiar forms taken by the metallic sign in Plusia interrogations, 

 which appears to vary endlessly, whilst minor forms of variation in 

 the same markings occur in Plusia iota and pulchrina. Plusia aurifera 

 and illustris find places as British in our old text-books. The widely- 

 distributed bimaculata (verticillata as it was long called) is also con- 

 sidered a British species. P. ni is supposed to have been accidentally 

 imported, and moneta has recently been added to the British fauna, a 

 considerable number of specimens having been taken during the last 

 two or three years. Altogether this is a most interesting family, and 

 a general favourite among lepidopterists. Of the Plusiini, Grote 

 writes : " The thorax is rather short and square, but globose above, 

 with hairy, somewhat silky covering, which forms, posteriorly, an 

 abrupt tuft. The eyes are naked, lashed in Plusia, unlashed in Telesilla. 

 The wings are somewhat pointed with full external margins. The 

 tibiae are unarmed. The ornamentation of Plusia is remarkable for 

 the silvery or golden middle marks, or sheeny patches. The American 

 species are forty-two in number, exceeding the European thirty-eight ; 

 but, probably, more remain to be described with us. We have repre- 

 sentative species, e.g. putnami, allied to the European festucce, while 

 parilis is found in Lapland and Labrador. The question whether ni 

 can be separated from our brassicce, I have been inclined to answer 

 negatively. The peculiar abdominal tufts speak for the identity of the 

 forms. Among American forms are a greater number of grey and 

 brown species, allied to gutta, interrogationis, chalcytes, &c., and are 

 perhaps, on the whole, less showy. Nevertheless, a resemblance may 

 be traced between many species, as between v-argenteum and mappa, 

 zosimi and balluca, etc. The resemblance is further shown in the species 

 of Habrostola, which have the caterpillar 16-footed and the moths 

 without metallic marks, while the species of Plusia have 12-footed 

 larvaB. But the most remarkable among the American species of Plusia 

 are the three mimetic forms : thyatiroides which resembles a Thyatira, 

 formosa which resembles a Leptina, and striatella which resembles a 

 Heliophila (Leucania). Behrensia is a Californian type, allied to 

 Habrostola ; and Deva, an eastern and western genus, is closely allied 

 to Plusia " (' Canadian Entomologist,' vol. xxii., pp. 70-71). 



Abrostola, (rect. Habrostola), Gn. 

 Structurally, the larvae of Abrostola connect the Plusidce with the 



