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Show 1897.] ON THE CLASSIFICATION OF THE THYRIDIDEE. 603, and possibly Phaneropleuron, approached more closely to Ceratodus than did Dipterus and its allies. The last-mentioned Dipnoi, on the contrary, seemed to represent a divergent and terminal branch of the Dipnoan stem and to include the most highly specialized examples of the group. This memoir will be published entire in the Society's ' Transactions.' The following papers were read :- 1. On the Classification of the Thyrididee-a Family of the Lepidoptera Phalsense. By Sir G E O R G E F. H A M P S O N, Bart., F.Z.S. [Received April 8, 1897.] The Thyrididee, of which a classification is here given, is a small famdy of Lepidoptera closely related to the ancestral stock of the Pyralldce, in which family they are most nearly allied to the Indian Slmcethlstls and to two Australian species, asurldla, Butl., and magnified, Meyr., for which a genus requires to be made. Most of the genera have veins 2 to 11 of the fore wing arising from the cell, and vein 8 of the hind wing approximated to 7 at or beyond the end of the cell, not anastomosing with 7 as in the majority of the Pgralldce. These characters show a very generalized type of structure, but as specialized developments we have the abortion of the maxillary palpi and of the vein in the submedian fold of the bind wing, which prevents their being regarded as the ancestors of the Pyralldce, in all of which tbe latter character is retained and also the former in all except a specialized subfamily, the Chrysauglnce. Erom the Thyrididee were derived the Drepaniclce, closely related to them and differing principally in the more complicated neuration of the subcostal veins of the fore wing and in vein 1 a of the hind wing being absent or short, these again giving rise to the small Oriental day-flying family Callidulldce; the whole group of families, which includes also the Pterophoridce and Orneodldte, having sprung from the Tlneld stock near the ancestors of the Sesladce and Zygcenldce. The Thgridldce are almost entirely confined to the Tropical zone; the genus Thyrls itself is Falsearctic and Nearctic, but of the rest of the family only two or three species spread into the Southern States, a few more to Japan and N". Asia, and one to N e w Zealand. The ancestral form of the family would have short porrect palpi, all the veins of the fore wing from the cell, the hind wing with vein 5 from the middle of the discocellulars and vein 8 free; with such a form Morova conforms except that veins 8 and 9 of the fore wing are stalked. Erom this ancestral type have developed forms of abnormal shape and appearance culminating in Hepaliodes-forms with the subcostal neuration of tbe fore wing modified in various ways, such as Beguma, Plagiosella, and Pgcnosoma, and forms with the discocellulars aborted, such as Glanycus and Thyrls. |
