CHR YSOMELID AE . 



195 



sexual character of the male. In some species in the male the basal segments 

 of the antennae are dilated, while in others this dilatation is absent. The 

 particular nature of the dilatation has also been pressed into service to separate 

 species among those that have males with dilated basal segments. It may be 

 remarked that species in which the basal segments are not dilated in the male 

 nevertheless have these segments somewhat thicker in the male than in the 

 female. The black patches on the elytra, on the head and on the under side of 

 the body are variable within a species, and transitional forms exist, but these 

 markings have been used in separating species. 



It is quite probable that Galleruca austrocaledonica Montrouzier, Ann. Soc. 

 Ent. Fr. (4), i, p. 299, 1861, and Aulacophora tetrastictoptera Lea, Mem. Queens- 

 land Mus., viii, 1, pp. 50-1, 1924 (cotypes in the British Museum) are identical 

 with A. (Crioceris) quadrimaculata F. ; but the question can never be definitely 

 settled because the Fabrician type in the Banks Cabinet is a female, and it is 

 impossible to ascertain whether the males of the Fabrician species have the basal 

 segments of the antennae dilated or not. Moreover, the female of the Fabrician 

 species agrees closely with the females of several other species, whether the males 

 of the latter have dilated segments in their antennae or not. The difficulties 

 that have arisen here cannot be settled by the comparison of structural characters. 



In these circumstances I propose to call the Samoan species by the oldest 

 name given to this type of insect occurring in the regions under study, and 

 I suggest that experimental breeding be undertaken by those who have the 

 opportunity, in order to ascertain whether we are dealing with a single species 

 with dimorphic males. 



Variation in the Samoan Specimens. 



1. The males are somewhat smaller, and have the basal segments of the 

 antennae simple, i.e. not dilated. 



2. The postocular black patches vary in size ; in one or two cases they 

 have become larger, and have coalesced in the interocular space. 



3. The elytral patches also vary in size ; their boundaries are sometimes 

 well defined, sometimes irregular. Among the examples from Savaii, the 

 posterior elytral patch is enlarged and sends off extensions to meet the anterior 

 patch. It is possible to conceive a case in which the whole elytral surface 

 might become black owing to the enlargement and confluence of the four elytral 

 spots. 



