39 
British truneata, there are several very short basal spines, etc. Packard 
(Monogr. Geom., pi. vii., fig. 24, 24a, 24b) gives some figures of the 
genital armature of what he calls truneata, but, unfortunately, does 
not show the spines. 
The difficulties in the way of unravelling the synonymy of two 
such closely-allied species as we have before us this evening are, 
naturally, very considerable, and in dealing with some of the older 
and more incomplete descriptions one has to be guided by the impor¬ 
tant principle, laid down in the “ Merton Rules,” that the earliest 
determination is to be accepted unless it can be proved erroneous. 
The greatest stumbling block has been Linne’s name of citrata, erected 
m the “Fauna Suecica,” ed. ii., p. 332 (17G1). The Linnean 
diagnosis and description run thus :—1265. “ Ph. Geometra citrata 
seticornis, alis griseis macula subterminali albo-fulva strigaque alba, 
apicis lineola fusca. Habitat in foliis Citri, quae noctu edebat. Larva 
geometra viridi-pallescens (Rolander). Magnitudo Ph. piniarife. Abe 
sup. supra grisere ; juxta marginis crassioris postica macula magna 
alhida, postice subferruginea, quam excipit striga alba tenuissima 
undulata ; in apice alas litura litura [sic] linearis nigra, ut duabus 
prrecedentibus [*.<?., chenopotliata and comitata'] . Subtus cinerete, postice 
pallidius.” Probably this was described from a specimen which was 
bred by Rolander and never passed into Linne’s posession. At any 
rate there is no reliable “type” in the Linnean collection. There is 
a Geometrid with a label “ Citri” in ink and “ Fn. Suec. ? 1265 ? ” 
added in pencil, and a second (later) label “ citrata, Fn. Su. 1265 ?” ; 
but, for several reasons, no importance can be attached to it. In the 
first place, though I fancy the original “ Citri ” was in Linne’s hand¬ 
writing, there are two pin-holes in the label, so that it is probably one 
of those which got displaced in the adventurous voyage of the collec¬ 
tion, and the queries in subsequent labelling confirm this ; and in the 
second place, though it may likely be a bred specimen (the left wings 
being crippled), it is hopelessly at variance with the description. It 
has had some rough handling—the abdomen and right antenna being 
broken off and the thorax rubbed—the wings are not set, and it was 
not without some difficulty that I recognized it as a small $ specimen 
of Cleora cinctaria, Schiff. Even if we may allow that there is room, 
for some latitude in picturing the exact relationship and pose of the^ 
markings indicated by the Linnean description, and notwithstanding 
the known variability of C. cinctaria, the mention of a large whitish 
posterior spot on the costal margin would render a reference to that 
species very difficult, while the emphasis laid on the apical black mark 
—“ as in chenopodiata and comitata ”—settles the question against it. 
So far as I can find out, Phalaena Geometra citrata, Linn., remained 
undetermined, and almost uncited for nearly a century. It attracted 
the attention of Werneburg when he commenced his researches in the 
nomenclature and synonymy of the eighteenth century,and in 1855 in an 
article “Feber einige Schmetterlinge alterer entoniologisclier Schrift- 
steller ” (Stett. Put. Zeit., xix., pp. 49-57), he determines it as a form of 
truneata, Hufn. = r«ssfltfl, Schiff. He admits that at first sight his 
determination, if compared, for example, with Treitschke’s description, 
might appear somewhat rash : hut he defends it on the grounds of the 
extreme variability of the species and consequent difficulty of adequate 
xviii. 
