The family of the Pyrrhocoridæ is rather well represented in the collections of the Leyden Museum, so that it seems me to be of use to publish a catalogue of the specimen after having identified them. The specimen in the collection of the Leyden Museum are of very different origin, as it will be shown in the following catalogue. Of course the Malayan archipelago is the best represented region, and in many cases the list of localities in this paper will throw quite a better light upon the geographical distribution of several species. Besides there were twelve new species from the Netherlands east Indies in the collection, that is about l/6 of the species already described from this region. During the last year the Museum obtained a notable number of partly very interesting specimen from the firm STAUDINGER & BANG-HAAS at Dresden-Blasewitz, to whom I am very thankful for the manner in which they placed their material at my disposal. A short visit to the British Museum enabled me to have a look at the types of different authors, specially of F. WALKER, W. L. DISTANT and J. C. FABRICIUS. The examination of these types showed me that there are rather a lot of false interpretations still in the litterature of the last years. I have mentioned all these, in so far as they give cause to a changement of the arrangement as given in the General Catalogue of the Hemiptera Fasc. III by R. F. HUSSEY (1929). I am indebted very great thanks to the curator of the Hemiptera in the British Museum, Mr. W. E. CHINA, for his advices and for the assistance when I was working at South Kensington. The classification and the order of the species in the following list is