ON SOME VARIATIONS OF APHANTOPUS HYPERANTHUS. 251 



expression in the variety arete; ocellus No. 4 is almost always con- 

 joined with No. 5, and is frequently small and of the arete form, 

 while ocellus No. 8 is almost invariably of arete form, though it 

 stands quite apart from its predecessor, No. 7, being sharply 

 separated from it by the lowest median nervure, and when we 

 come to the variations it is in these two ocelli, as may be expected, 

 that the difi'erences from type are first seen ; it is these ocelli 

 which tend to become obsolete more frequently than the rest, or, 

 in the arete forms, they are apt to degenerate into mere eosca points. 



We find that the insects in which the typical is combined 

 wdth the arete or caeca form are exceedingly rare. However, of 

 the forms type + arete (group A), and type + cceca (group B), 

 we have several examples. In these insects it is the ocelli on the 

 upper wing which remain typical, and almost invariably they 

 are ocelli Nos. 1 and 2 which keep the typical form ; ocellus 

 No. 3 is either arete or caeca in form, or else obsolete ; but we 

 have one interesting example in which the first three ocelli (those 

 on the fore wing) are boldly typical, while all those on the hind 

 wing are particularly minute caeca points. It should be noted, 

 however, that ocellus No. 3 is more prone to obsolescence than 

 any other ; in every variation of the insect, as well as in the two 

 groups just noted, it is the first to disappear. 



We now come to the true arete variation, which we have 

 ventured to designate as group C. In it the size of the ocelli 

 are much reduced throughout ; on the fore wing ocellus No. 2 

 tends to stand out most boldly and to approximate most closely 

 to the typical size and form, while on the hind wing ocellus No. 

 6, the first of the last group, persists most strongly, closely 

 followed, in this respect, by ocellus No. 5. 



Group D, in which the arete and cueca characteristics are con- 

 joined, affords many most interesting variations. As may be 

 expected from what has been already said, ocelli Nos. 1 and 2 on 

 the fore wing usually persist as arete when the remaining ocelli 

 have passed into caeca points. We also find that in these examples 

 ocellus No. 3 has completely disappeared, as has ocellus No. 4, 

 while ocellus No. 8 has, in most instances, become either obsolete, 

 or else is reduced to a mere microscopic point. 



Finally we come to group E, the true ca;ca variation. In this 

 form the fore wing is almost invariably obsolete, although we 

 possess one or two specimens in which ocelli Nos. 1 and 2 remain 

 as almost indistinguishable points. In the hind wing we 

 generally find that only three ocelli are represented by caeca 

 points, these being Nos. 5, 6 and 7, the last of the first group 

 and the first two of the second group upon this wing. We have 

 never met with complete obsolesence (var. ohsoleta) ; we possess 

 two or three specimens closely approaching this form, but in all 

 of them the three caeca points, already mentioned, still remain 

 quite clear, although exceedingly minute. 



