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Show 480 MR. A. G. BUTLER ON [Nov. 4, butterflies crossing the Red Sea in the very teeth ot a strong wind." There would therefore be nothing very extraordinary in the flight of some of the larger species across the Strait of Bab-el-Mandeb, more especially if the wind chanced to be in their favour. Lest there should be any doubt in the minds of Lepidopterists as to the specific identity of the four forms of Aden, I quote here Major Yerbury's note on the species:-" I have taken dorippus and chrysippus ' in coitu ' so often that I have given up catching them as a curiosity : I have raised caterpillars feeding on plant no. 411; there seemed no difference between the caterpillars which turned to chrysippus and those that turned to dorippus. The chrysalides were of two colours-green with gold spots, and light waxy purple with ditto."-J. W . Y. From notes attached to the specimens, it would appear that the green chrysalis produced the Indo-African form of L. dorippus and the purplish chrysalis L. chrysippus and intergrades towards L. alcippus. It is a singular fact if there really is not even a slight difference between the larvae of the various forms. The question now arises as to what the systematist is to do with these four forms, since they are (so far as is known) good species everywhere, excepting at Aden. If we apply to them trinomial appellations, calling one Limnas chrysippus alcippus, another Limnas chrysippus dorippus, and so on, we declare that they are local races of one species ; and yet as a matter of fact they both are and are not. Again, supposing tbe trinomial system to be generally adopted for local races, though it would practically (if not always immediately) reduce every genus of Lepidoptera to a single species, and eventually as links continued to turn up (so as to necessitate the union of nearly allied genera) might lead back the lepidopterist by a process of l'etrogression to the first described butterfly, nevertheless, though all these evils might spring from the adoption of this system, Limnas chrysippus and one or two other Aden butterflies could not be embraced by it, because at Aden their forms are not local but mere polymorphic sports, or in a word true varieties. In the present paper I shall keep the various named forms separate, though under one number, the first as a matter of convenience, to enable m e to record the exact place and date of capture, the second to indicate that at Aden they are not distinct species. RHOPALOCERA. NYMPHALID^E. EUPLCEINJE. 1. LIMNAS CHRYSIPPUS. Papilio chrysippus, Linnseus, Mus. Lud. Ulr. p. 263 (1764). One typical female, Aden, 26th February, 1883. Taken in coitu with Indo-African type of L. dorippus. 1 I cannot get the name of this plant. |