76 THE entomologist's record. 



basal-fleck is not continued upon the shaft, this being quite excluded 

 from the area occupied by the basal-fleck, and is, indeed, more or less 

 distinctly separated from the hind border of the latter by a fold (fig. 8). 

 Thus, a reduction of the basal-fleck takes place in the more specialised 

 families. 



The differentiation of the structure of the basal-fleck always begins 

 with a reduction of size and number of the distal, or, in general, the 

 peripheral cones ; the proximal ones (ordinarily standing closest to- 

 gether) become, on the other hand, more highly developed (fig. 7). 

 In consequence of this, the form of the area, occupied by the cones, 

 undergoes many changes. In the less modified members of several 

 groups it represents a wide cuneiform, or somewhat gradually tapering, 

 area, along the middle of the proximal, and widest, portion of the 

 basal-fieck (PI. I., fig. 1). A further reduction of the distal cones and 

 an increase in the size of the proximal ones lead to a still greater 

 contrast between them, the result often being an entire obliteration of 

 the former, while the latter only remain ; the area itself is, in this 

 case, though variable in shape, generally well and distinctly defined. 



At the same time, the proximal part of the basal-fleck, which on 

 the whole exhibits a high degree of plasticity, often becomes more or 

 less distinctly swollen. This swelling, in the various groups of 

 Khopalocera, is dissimilar in form, and presents varying degrees of 

 development, frequently, as in the more specialised members of the 

 Danaidinae, Morphinae and NymphaUnae, being very strongly differen- 

 tiated and conspicuous, and occupying almost entirely the basal-fleck 

 area (PI. I., figs. 2-4). Sometimes, as in the Lycamidae, the process of 

 diflerentiation gives rise, not to a swelling, but to a transparent area, 

 which is often very sharply defined, and as clear as water (fig. 5.) Now 

 and then a secondary reduction of the swelling takes place, but after 

 this the swelling is never re-developed. 



"Where a swelling has been strongly developed (even though after- 

 wards reduced), and the distal cones obliterated, as, for instance, in 

 the more specialised I\<?irti(Zi»rtt', Morpldnae, Brassolinoe, and, above all, 

 in the higher NymphaUnae, the proximal cones, restricted to the 

 swelling only, often attain a very high degree of development, being 

 robust, and somewhat curved in shape, sometimes regularly arranged 

 in parallel form, and directed upwards. Rarely, as in Euselasia and 

 MetJioneUa, the process of reduction, beginning with the distal cones, 

 results also in the entire disappearance of the proximal ones. The 

 pits, few in number, situated on the middle or distal half of the basal- 

 fleck, sometimes (in some Nymphalinae) enter into the distal portion of 

 the swelling, but, being concealed by the overrunning cones, are then 

 rather difficult to detect. 



We find, thus, that all the gentes in their least modified, i.e., in 

 their lowest, members, differ slightly from the primitive type described 

 above, and also from each other. From this type different lines of 

 development proceed, diverging more and more, and often leading, in 

 the most specialised branches of the different gentes, to very dissimilar 

 forms, unless a secondary convergent process of differentiation has 

 taken place, as is sometimes the case. Another very remarkable fact 

 connected with that just stated, is, that the extremes, i.e., the most 

 specialised and the most generalised forms of the name gens, differ, on the 

 whole, much more strongly from each other than do the most primitive 



