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it is necessary to give a review of each antennal organ and strnctnre that we have 

 described above, taking into consideration, not only the antennae of Butterflies, but 

 also such chief stages of development of these organs as I have met with among 

 Moths, in so far as these stages are of importance for onr present purposes. 



a. The Scaling. — The number of Lepidoptera which have not-scaled antennae 

 is very small in comparison with the number of species that bear scaling at least 

 on the dorsal surface of the stalk, and even the antennae which I call uot-scaled have 

 in many cases the most proximal joints sparsely scaled above. Among Heterocera 

 I have found not-scaled antennae only in a few families. The Eastern Uepialidae 

 have mostly the antennae bare of scales, while in most American species (all ?) the 

 dorsal side is scaled to a more or less great extent. The Saturniidae, inclusive of 

 Ccratocampidae, have not-scaled antennae, with the e.vception of Diaconipteris, 

 Teratopteiis, and Oxytenis, which, in my opinion, are not Saturniids. The genus 

 Amerila, which stands rather isolated among the Arctioid Moths, has also not-scaled 

 antennae. Whether there are any Tineidae that belong here I do not know ; all 

 the species I could examine have the antennae scaled. The proportional number of 

 species without scales on the antennae (except the three to six basal joints) is by far 

 larger among Butterflies ; but here again such antennae are not found in members of 

 all the families, but are confined to the Papilionidae and Nymphalidue, not a single 

 species of Hespcriidae, Lycaenidae, Erycinidae, or Pieridae having the antennae 

 not-scaled. The absence of scales is a constant character in several groups of 

 Papilionidae and Sympkalidae ( Thaidinae, Danainae), while in other groups of 

 these families the character occurs only in a very restricted number of species (some 

 Parnassius, Morphinae, Satyrinae, etc.). In a few Pieridae (^Mesapia and allies) 

 the scaling is very sparse, but not absent. 



Is the not-scaled antenna the one extreme in the development of the 

 scaling, the totally scaled antenna would be the other extreme. However, there 

 is not a single Lepidojjteron in which the entire surface of the antenna is covered 

 with scales. In every species there is a space, varying in extent in the different 

 species or groups of s])ecies, left bare of scales, a space bearing sensory hairs ; and 

 this not-scaled area is either entirely restricted to the ventral surface of the 

 antenna,* or, if the dorsal side participates of it, its ventral extent exceeds the 

 dorsal extent. In no case is the ventral side all scaled and the not-scaled space 

 restricted to the dorsal side, nor is the area more extended dorsally than vcutrally; 

 and again, if the not-scaled area extends upon the dorsal surface, it is always the 

 distal portion of the antenna that is without scaling ; it never occurs that the apical 

 joints are scaled above and the more proximal joints are bare of scales. 



Tliere is a series of iutergraduate stages between the not-scaled and the almost (!) 

 completely scaled antenna in Butterflies. 



Among Moths I have not come across such iutergraduate stages, except in 

 Uepialidae, where the antennal scaling, if present, varies from occupying the entire 

 dorsal surface to being restricted to the proximal half or third. In all other Moths 

 the dorsal side of the antennae is scaled, inclusive of the last joint ; in species with 

 long pectinations the branches are, however, often bare of scales. Snch a great 

 extent of the dorsal scaling as found in the Heterocera (except the few forms with- 

 out antennal scaling, and certain Uepialidae) is not so often met with among 



• The not-scaled area is not in the middle o£ the ventral surface, but is intemo-ventral ; in the 

 antennae with dark upper- and pale underside the line of dgmarcation between the two colours is often 

 rather sharply defined. 



