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The President mentioned that Mr. Darwin was engaged in elaborating the subject of secondary sexual differences and sexual selection and would be obliged by the communication of detailed observations on the numerical proportion of the sexes of insects in nature. He had numerous cases of well-authenticated numerical excess of the male over the female, and was desirous to ascertain whether in other cases a coresponding excess of the female over the male had been noticed.

Mr. M'Lachlan mentioned Apatania Muliebris, of which he had captured hundreds, but the male had never been seen; and Boreus hiemalis, of which only three or four males had been known to occur in this country. Mr. Janson mentioned Tomicus villosus, the female of which was almost a plague, whilst the male was hardly known. Mr. S. Stevens referred to Drilus flavescens, the second known British female of which was exhibited at the previous Meeting ('Entomologist,' iv. 81). Mr. F. Smith cited Tenthredo cingulatus, the male of which was rare, whilst the female abounded, and Hemichroa Alni, of which the male was quite unknown. Of the latter Mr. Smith had a large number of cocoons, and if there were such a thing as a male of that species he hoped soon to breed it.

The President remarked that the different habits of the sexes must be taken into account. Among the South-American butterflies, the males of many were more handsome than the females, and exceeded them in number in the proportion of a hundred to one; the male sported in the sunshine, whilst the female was slow in flight, never appeared in in the open sun, but remained in the shade of the forest: under such circumstances it might be that a superabundance of males was necessary in order to ensure the impregnation of the females and to prevent the extinction of the species; but he was unable to suggest any explanation of an excess of females over males.

Mr. Stainton thought that, by reason of the difference of habit of the sexes, little reliance could be placed upon records of a supposed disproportion of the number of the sexes of any insect when in a state of nature: it was only by breeding the insect that the relative numbers of the sexes could be ascertained with any certainty. In Micro-Lepidoptera he

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had often found the result of observations in the field at variance with the result of breeding the same species in confinement; species the females of which, from their retiring and secluded habits, were seldom caught, whilst the males were common, had, when eggs or larve were obtained, produced twice as many females as males.

Mr. McLachlan said that Mr. Darwin had recently put two queries to him. Do male dragon-flies fight with one another? and, Do many or several males follow one female? He confessed his inability to answer with certainly either of these apparently simple questions.

With reference to the numerical disproportion of the sexes of insects, Mr. Stainton mentioned that since the previous Meeting he had inquired the results of the experience of Mr. Doubleday and Mr. Hellins in breeding Micro-Lepidoptera. Mr. Doubleday thought that males were generally more numerous than females, and did not remember a single instance in which he had met with an excess of females. Mr. Hellins, on the other hand, reported that he had usually: found females more numerous than males.

Mr. Stainton added that Mr. Darwin would be glad to receive replies to the following further inquiries:—(1), whether sexual attraction or fascination was exercised in the same manner by butterflies which have the wings gaily ornamented on the under side and by those which have dark under sides, as e. g. by Argynnis and Vanessa; (2), whether: any and what moths were more brightly coloured in the male than in the female sex; and (3), whether any and what moths were more conspicuously coloured on the under side than on the upper side of the wings. (In reply to the third query, Nr. Wormald mentioned the genus Hypopyra). Mr.

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Darwin was also desirous of acquiring facts bearing on the distinction between sexual and protective colouring in insects; and of ascertaining the causes which decided the success of one out of several males which were in pursuit of the same female.