LYCAENIDAE. General Topics by Dr. A. Seitz. 741 



foreign to the Lycaenidae in other parts of the world. Solely the Eumaeus which we shall have to mention later 

 on also in a biological respect, deviate in manifold respects also in the structure of the body. 



The most conspicuous part of the wings are the hindwings, in which the formation of delicate, small 

 tails m the anal region has sometimes degenerated into long, thin, soft filiform appendages. Particularly the 

 Thecla of the imperialis-gvoup exhibit these formations which appear even more loosely arranged than those 

 of numerous Indian forms, -such as the Sithon and their allies. The long, sword-like or sabre-shaped tails, as are 

 found in so many Indians (e. g. Loxurn), do not occur in a similar development in America. But the longer 

 appendages to the hindwings of some species are so delicate and soft that they dangle to and fro at the least 

 puff of the wind. It is strange that these fine formations do not suffer more from the flight which is impetuously 

 swift in some of these long- and thinly-tailed species. Nor do these tails, on capturing the animals in the net, 

 break off as easily as one might fancy, considering their fineness, and I repeatedly captured much-flown and 

 otherwise damaged specimens of Thecla impenalis in which the delicate appendages were well preserved. 



Another peculiarity in the shape of the hindwings of the American Thecla are the small anal lobes 

 which, being situated proximally to the filiform tails, may be of a laciniform or bossy shape. Like in many 

 palearctic species, they are often so long that, in the resting butterfly, they reach down as far as below the 

 anal end of the abdomen and would thereby be inconvenient, for which reason they are bent down rectangu- 

 larly to the surface of the wings. 



The proximal margin of the hindwings is mostly slightly bent in, but it may also be distorted to a deep 

 indentation or notching. Exactly where, in the sitting butterfly, the apex of the abdomen rests on the support, 

 there is in some species, such as Thecla latraillei, a strange indenture in the margin of the wing as if to render 

 the sexual organs accessible to the copulation which organs, in encasing the abdomen, would otherwise be 

 covered by the inner-marginal fold of the hindwings. The clasping-organs of the male, as much as is evident 

 from the very scarce material examined so far, seem to be still more conformably built than in the Erycinidae; 

 up to now the examinations of the clasping-organs have not yet yielded any surprising systematic results. 



On the other hand, very many American Lycaenidae exhibit the scent-spots and male scales, which 

 have already been profoundly studied in the European species. The former organs, serving according to one 

 hypothesis for producing the scent, are found in very many Theclini, where they almost invariably are placed 

 near the end of the forewing-cell and are exhibited as oval, more rarely circular, scale-pads of a red-yellow, 

 brown or black colour, which are particularly bright and prominent in those species the upper surface of which 

 exhibits a blue or golden-green metallic lustre which is absent in those scent-pads. 



These pads exclusively occur in male specimens and are immediately noticeable for instance in Thecla 

 gemma, sista, aurora (t. 151 a) and other Thecla, as well as in European Theclini (Callophrys rubi etc.). They 

 consist, however, of scales showing no essential structural differences from the normal wing-scales, nor has 

 there been, according to Couevoisibr, a proof produced of their function of producing the scent, though one 

 cannot fail to recognize that a function of the male sexual activity is due to them. 



We must distinguish from these the modified male-scales considered as real androconia and distributed 

 over the upper surface of the wings, the structure of which was exhaustively investigated by Kohler 20 years 

 ago and recently by Courvoisier. They are sometimes apparently irregularly scattered across the surface 

 of the wings, but mostly arranged to zones, stripes and bands which sometimes show a certain relationship 

 to the shape and marking of the wings. They were sometimes found to be of the shape of a tennis-racket 

 (Watson), or sometimes utricular or vesicular (Anthony), and Illig discovered at the bafe of their footstalk 

 glandular cells which he presumes to discharge their secretions over the scale thus representing in a certain 

 manner a bowl for the evaporation and production of the scent. This agrees well with what Courvoisier ascer- 

 tained later on viz. that the shape of these scales is not that of a balloon, but more of a spoon. 



On this occasion, the latter investigator also discovered the systematic applicability of these androconia. 

 He evidenced for quite a number of species a characteristic formation adherent to the species. He was able 

 to follow up the same forms of scales through a great number of aberrations, local forms and geographical races. 

 In most cases all the forms belonging to one total species showed the same structure of the male scales, and 

 numerous changes in the homogeneousness of subspecies and local races were proposed bj' reason of these 

 investigations. The finer structure exhibited a steady number of the separate species of longitudinal ribs exten- 

 ding over a finely reticular surface. The transverse meshes, at the junctions show verrucous knots forming 

 again characteristic figures, so that Courvoisier comes to the conclusion that these scales are at least just 

 as fit for specific differentiations as the clasping-organs. 



Opinions differ greatly as to the intrinsic properties of these scales. They have been looked at as mal- 

 formations of normal scales, or also as air-bellows in order to assist the flying-activity. Kennel thinks that 

 originally both sexes had been provided with such scales, but that these had then been lost by the females. 



