| OCR Text |
Show 530 MR. L. DONCASTER ON COLOUR-VARIATION [Dec. 12, found that of the males 81 per cent, were spotted with dai undersides, 19 per cent, striped only with light undersides, found rather over 83 per cent, spotted and dark, 16 per cent, striped and light, and about 0'5 per cent, with intermediate undersides. Of the females, I found 27'5 per cent, with dark undersides, the same proportion as was observed by Bateson. The occurrence of the different varieties is in every way in close agreement with that found by Bateson ; and it may be concluded that their distribution at that season has not changed appreciably in ten years. I did not collect in the Darro valley from which Bateson's second sample was obtained, but I found that on the lower slope of the hill towards the Genii valley the proportions did not differ from those on the top. On the Darro slope of the hill, which is very steep and faces north, the beetle did not occur, although Spartium was abundant. At Granada a considerable proportion of the beetles were in cop., and I collected 119 couples and recorded the characters of each as they were gathered. Care was taken to see that they were really paired, and since 71 pairs remained coupled after they were dead in the killing-bottle, there can be little doubt that all or nearly all were really in cop. Table II. gives an analysis of these. Of the 119 pairs, there were 22, or over 18 per cent., in which both male and female were striped green with light undersides. Taking pairing at random among the general population the expectation would be 10'5 per cent. But the proportion of males of this type which were paired is considerably higher than in the general population (29 out of 119 or 24-4 per cent.); so that random mating out of those paired would give 17 per cent, of such pairs, which does not differ greatly from the 18 per cent, observed. Similarly there were 25 pairs (21 per cent.) in which both male and female were red with dark undersides. The expected number on random mating among the whole population is 15-2 per cent., on random mating among those actually found paired about 17 per1 cent. The numbers observed are of course much too small to give reliable conclusions, but they indicate that of the males of the green striped form, and females of the red spotted form, a slightly higher proportion is found paired than in the general population, and that there is possibly a very small tendency towards selective mating between individuals of the same colour type. At Ronda Spartium bushes were very scarce, and upon many there were no beetles, so that altogether only 106 individuals were obtained, 80 of which were males, 26 females. Although these numbers are small, they indicate that the population differs considerably from that of Granada (Table III.). Of the males 60 (75 per cent.) were spotted and dark underneath, 9 were green, striped and light, one red, spotted and striped, light, and 10 red, spotted and striped, with intermediate undersides. At Granada only 6 intermediates occurred in 1382 specimens; while |
