New Lepidoptera collected by Mr. T. A. Barns 51 



NYMPHALIDAE. 



The genus Erg oils Westw. 



The species enotrea Cram., is associated with a form which closely 

 resembles it but differs especially in the possession of patches of 

 modified scales on the wings below in the 3~ . 



The species actisanes Hew., which possesses in the £ a large area 

 on the hind wing covered by modified scales, is associated with a form 

 in which this area is absent. 



We have examined the genitalia of the four forms and find two 

 well marked types indicating a great distinction between enotrea and 

 actisanes, but less distinction between either and the form resembling 

 it in pattern. 



One may perhaps consider the probability of the existence of a 

 dimorphic form in connection with both these species, and that a 

 certain dependence of this form on the seasons may have led to further 

 divergence in structure. 



At present we have no data to support this view, but we think 

 that interesting results would be obtained from breeding experiments. 



We think it is not impossible that species may evolve from closely 

 allied forms in the same locality through the agency of seasonal and 

 sexual dimorphism, and changes in the flight-time of the sexes. 



Genitalia. — The Ergolis examined are characterised by the posses- 

 sion of two highly-chitinized symmetrical plates. These plates are 

 disposed bilaterally on the ventral side of the genital apparatus, and 

 we call them the ventral plates. They are connected with the valves 

 by a membrane bearing setae on one side. We call this the con- 

 necting setose membrane. Its position is the same in actisanes and 

 albifascia, but differs in enotrea and personata. 



The genitalia of enotrea and albifascia show more resemblance to 

 one another than to either actisanes or personata, whilst these two 

 latter are similar to one another. 



Owing perhaps to a faulty dissection of the insects, a structure 

 represented in the drawing of enotrea by a dotted line, and which 

 probably is the chitinous cone at the base of the valves (ring-wall, 

 penis funnel, and juxta of authors), has been missed in the other 

 forms examined. Further investigation will be made in reference to 

 this structure. 



