1895.] COLOTJE-VAEIATIONS OF A BEETLE. 851 



the surface. Several other species of Spartium grow in the south 

 of Spain, but I did not find G. variabilis on any of them. Never- 

 theless, living specimens brought home to England ate the shoots 

 of S. jundfolium, with which they were provided from the 

 Cambridge Botanic Garden. 



It was at Granada, on March 28, 1894, that I first saw G. varia- 

 bilis and was at once struck by the great variety of appearance 

 presented by different individuals. In a few minutes I came upon 

 most of the chief kinds, including what will be described as the red 

 form with black spots, the greenish-grey form with black stripes, 

 a totally black form, &c. As may be seen from the figures (Plate 

 XLVII.) these different varieties are strikingly unlike in general 

 appearance, and not having previously heard of this beetle I at first 

 doubted whether all were one species. Then, finding specimens of 

 dissimilar colours coupled together, I concluded that they did all 

 belong to the same species, and as all intermediate forms were 

 afterwards found, there can be no doubt on this point. Subse- 

 quently Dr. D. Sharp, to whom I am indebted for much help in 

 examining these specimens, gave me the name of the beetle and 

 told me that it was known to undergo great variation in colour^. 

 I may add further that no difference could be seen in examination 

 of the sedeagus of the several forms. 



It appeared that the case was worth further investigation with 

 the object of determining with what frequency the various colours 

 occur, and to what extent specimens collected at random could be 

 grouped round special type-varieties to the exclusion of inter- 

 mediate forms, thus manifesting the phenomenon known as 

 organic stability in respect of those varieties. As so many 

 specimens were found in cop. it seemed further that by recording 

 the colours of specimens so coupled it might be possible to get an 

 indication whether there existed any operative sexual selection as 

 to colour. 



The next few days were spent in gathering a sufficient sample, 

 and I then returned to Gribraltar to follow other work. Very 

 soon, however, I found that the colours had so faded that the 

 collection already made was useless for my purpose. In fact, in 

 dried specimens the red and the green both usually fade to an 

 indifferent brown. I therefore went back to Granada and 

 gathered a fresh sample of about 1500. These I put into a large 

 wooden box and brought alive to England. In the following year 

 (1895) I returned to Granada and collected, on March 24—28, about 

 2500 more, recording all the colours at the time. 



It at once appeared that the colour is to a great extent 

 dependent upon sex, the males being generally of the red form 

 with spots like fig. 1, while the females are generally o the 

 greenish form with stripes like fig. 23, though every colour is 

 sometimes found in each sex. For this reason, before sorting the 

 specimens for the purpose of determining the frequency of each 



^ Several varieties have been briefly described by Weise (Deut. ent. Zeitschr. 

 1891, p. 160), but I infer that the colours were given from dried specimens. 



