1905. | IN THE BEETLE GONIOCTENA VARIABILIS. 533 
larvee 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 
has to the grey-green of the Spartiwm 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 septempunctata which frequently occurred on the Spar- 
tawm ; sothat 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 Spartiwm. 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 correlation 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 correlation was much less conspicuous, 
and at Malaga it did not exist. Further, it appears that the 
frequeney of the different varieties depends largely on season, 
but my observations did not extend over a long enough period 
to work this out thoroughly. At the higher, and presumably 
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 Spartiwm came into 
bloom, a pure green type appeared; and from the fact that no 
other form hatched from the larve 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, Cambridge, 
July 1905. 
