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JOURNAL OF VARIATION 



Vol. VIII. No. 10. November 1st, 1896. 



The Antennae of Lepidoptera. Their structure, functions and 



evolution. 



By J. W. TUTT, F.E.S. 



Ill his Evolution and Taxonomij,''-' Professor Comstock suggests 

 that "the logical way to determine the affinities of a group of 

 organisms, is first to endeavour to ascertain the structure of the 

 primitive members of this group, and then endeavour to learn in what 

 ways these primitive forms have been modified by natural selection, 

 keeping in mind that, in each generation, those forms have survived 

 whose parts were best fitted to perform their functions." 



Among the various structures that have been thus utilised as a 

 basis of study, in order to show which insects have a close genetic 

 relationship, are the antennae. f There can be no doubt that com- 

 munity of descent aflbrds the surest guide to similarity in the greatest 

 number of characters, and we can agree with Dr. Bodine that entomolo- 

 gists can now congratulate themselves that, " from a dry and wearying 

 process of sorting and pigeon-holing different forms for convenience in 

 management, we have advanced to a study of their development, and 

 the varying lines of descent through which they have attained their 

 present condition." 



The natural position of the antenn;B varies greatly in different 

 species. In some Lepidoptera the antennre " are directed nearly 

 cephalad ; in others, almost as nearly caudad, and all possible positions 

 between these extremes may be assumed." Dr. Bodine says, that after 

 considerable study of the natural attitude of the antennae in living 

 specimens, both in flight and at rest, the conclusion has been reached 

 that " the normal position is assumed when the antenna3 are extended 

 directly laterad, with the most specialised surfaces ventrad, and the 

 pectinations, where they exist, arising from the ventral surface," 

 although some exceptions are afterwards noted. 



The anteniiic belong to the preoral somite. They are slender segmental 

 organs, placed symmetrically one on each side of the meson, and in 

 the Papilionides and Hesperides, according to Scudder, and probably 

 in all other Lepidoptera, are inserted at the ends of the suture (PI. II. 

 fig. 7, cl. su.), between the epicranium (fig. l,ep.) and clypeus (fig. 7 



* "Evolution and Taxonomy," Wilder Quarter-Century Book, Ithaca, NY 

 1893, pp. 38-39. 



t " The taxonomic value of the antennse of the Lepidoptera," by Donaldson 

 Bodine, Trans. Am. Ent. Sac, .Jan. 1890. Price 3s. 



