Mr. A. G. Butler on the Genus liypocala. 17 



IV. — On the Genus Hypocala, a Group of JSoctuid Mollis. 

 By Arthur G. Butler, F.L.S., F.Z.S., &c. 



In the seventh volume of the ' Illustrations of Typical Lepi- 

 doptcra Heteroceni,' p. 76, I pointed out that the species of 

 Hypocala were trimorphic : this fact has led to so much 

 confusion that a revision of the species has become a neces- 

 sity. When once understood the forms of this genus are 

 easily recognizable ; the primaries on the upper surface vary 

 considerably, but always in the same way; the secondaries 

 and the under surface are constant in pattern in all the modi- 

 fications of each species. 



jM. Guen^e, -vvho would never identify an insect from a 

 rough figure, and yet rarely failed to describe every differing 

 form in his possession, however bad the specimen might be, 

 multiplied species unnecessarily. 



Whether from their rarity or the difficulty of capturing 

 these moths, I do not know, but they seem to come to hand 

 chiefly as individual specimens and at long intervals, so that 

 of several of the species only one, or at most two, of the 

 forms which represent the variations of each type have 

 hitherto found their way to us. Mr. Hocking seems to have 

 been more successful in collecting Hypocala than most men. 

 In his Dharrasala series we obtained all three forms of 

 H. suhsatura in the following proportions : — five of the 

 typical form, four of the variety H. aspersa, and four of the 

 variety IJ. limhata (the last-mentioned having, up to that 

 time, been unrecorded). 



In the following synopsis I propose to define the species 

 hitherto described with their varieties. In order to avoid 

 repetition in diagnosing the forms it may be premised that 

 any good figure (such, for instance,as that given byM.Guen^e, 

 ' iS'octu^lites,' iii. pi. xiii. fig. 7) will represent the general 

 characteristics in the pattern of the genus, if one allows for 

 the more blurred uniform character of the primaries in the 

 variety which I regard as typical, and the sharply defined 

 but melanic character of the form which I have characterized 

 as var. h. The secondaries are always ochreous and black 

 above, and the under surface is usually pale ochreous, more 

 or less marked with blackish and greyish. 



The under surface gives the best characters for the diflfer- 

 entiation of the species, and therefore I shall make my 

 primary divisions on points of difference to be seen on that 

 surface of the wings. 



Ann. & Mag. N. Hist. Ser. 6. Vol. x. 2 



