work. To this I have to add the Erycinidae. This group, so richly represented 

 in America, is closely related to the Lycaenidae and is indeed united with 

 it by some systematists. It is, however, represented in Java by only a small 

 number of species which, moreover, only occur in the mountains and, with a 

 single exception, are very rare. Although repeated excursions to the mountains 

 have been made by me, I have never resided there and only for a short time 

 at Buitenzorg, situate at the foot of the mountain range. In consequence I 

 have been unable to make a great number of observations, especially concerning 

 their ontogenisis, in connection with these butterflies, most rare even there. 

 I am, therefore, unable to venture on any explanation of the fact that of this 

 family, so numerous in America, the Austro-Malayan fauna possesses but a few 

 species. An adequate knowledge of the American forms would in fact be 

 indispensable for this ; for only by such means can an analogous phenomenon 

 in connection with some ancient Malayan Danais forms be accounted for. Such 

 knowledge, unfortunately, I do not possess. The Libytheidae, which Snellen 

 regards as a separate family, are not here included in the Erycinidae. They 

 are indeed but little related to the latter, not only as regards the difference in 

 form of the genitalia, referred to by Fruhstorfer, but also with respect to the 

 antennae and to their early stages. 



On the other shand the Lycaenidae are richly represented in Java, 169 

 species being known to me with sufficient certainty. I have indeed come 

 across several other species, in collections for instance, stated to occur in 

 Java, but whenever I entertained doubts as to the authenticity of the data I 

 have omitted them. No great accuracy with regard to such data was formerly 

 observed, and frequently "Java" was simply a general term for the whole 

 Austro-Malayan Archipelago, while many specimens which have reached Europe 

 from Java had been captured in other islands. The data supplied by dealers 

 in insects, likewise, are frequently unreliable. The collections made in Java, 

 or received from there by Fruhstorfer and myself, on the other hand form 

 a fair and safe basis to go upon. The Leiden Museum, moreover, possesses 

 many specimens from Java with the name of the collector, known to have 

 collected in Java, attached. 



As regards systematic division I have in this instance again made use of 

 the documents left by Snellen, at least as regards the general classification. 

 Since the aim of my work is totally different from a lepidopterist's system I 

 need not refer to the grounds on which Snellen based his systematic classi- 

 fication, nor to the keys he elaborated for it. Indeed, I do not attach much 

 value to this. Every systematist proposes, at least to some extent, new classi- 

 fications and frequently the one is as imperfect as the other. It will, therefore, 



