1905.] m THE BEETLE GONIOCTENA VARIABILIS. 533 



larvpe which hatched yielded this form, it probably replaces 

 the other varieties altogether. 



A possible explanation of the meaning of this seasonal change 

 occurred to me, when I noticed that the plain green form only 

 appeared when the bushes began to come into bloom. Bateson 

 has pointed out how close a resemblance the green striped form 

 lias to the grey-green of the Sparthmi twigs, and suggested that 

 the resemblance might be regarded as protective. So also the 

 red spotted type has a marked general similarity to the common 

 Coccinella septenvpunctata which frequently occurred on the 82)ar- 

 tium ; so that the red type of coloration may perhaps be considered 

 as mimicry of a species protected by its unpleasant odour. But 

 more close than either of these is the resemblance of the plain 

 green type to the flowers of the Spartium. The flowers are very 

 small and grow in clusters ; the petals are yellow, but are partly 

 covered by the bright green calyx. When a bush is in full bloom 

 the plain green type of beetle becomes almost invisible ; its thorax 

 is yellow corresponding with the yellow petals, and its elytra 

 have nearly the same colour as the calyx. The general resem- 

 blance is so close that the beetles are very hard to see when the 

 bush is in bloom, although when they are found on a plant which 

 has not come into flower they are nearly as conspicuous as the 

 , red type. 



My observations, taken as a whole, lead me to the conclusion 

 that the coiTelation between the two main forms of Gonioctena 

 and the two sexes, which Bateson observed at Granada, is a 

 special phenomenon depending partly on locality and partly on 

 season. At Ronda the coi-relation was much less conspicuous, 

 and at Malaga it did not exist. Further, it appears that the 

 frequency of the different varieties depends largely on season, 

 but my obsei'vations did not extend over a long enough period 

 to work this out thoroughly. At the higher, and pi-esumably 

 more backward, localities the males were more numerous than 

 the females, and the red spotted type was most abundant ; this 

 was most conspicuously the case in Bateson's collections from 

 Castillejo. Near sea-level there was an excess of females, and 

 at Palo this was associated with a predominance of green. 

 Finally, as the season advanced and the Spartixiim came into 

 bloom, a pure green type appeared ; and from the fact that no 

 other form hatched from the larvse which I collected, it seems 

 probable that in the summer this is the predominant type of 

 both sexes. 



In conclusion, I wish to acknowledge my indebtedness to my 

 brother for much valuable help in collecting the beetles. 



Zoological Laboratory, Canibridge, 

 July 1905. 



