In the present paper a revision is given of the Dutch material of two families of spiders in the van Hasselt Collection, viz., the Micryphantidae and the Linyphiidae. The greater part of the specimens have been collected by van Hasselt himself or by his family. Other well-known collectors, as Everts, ter Haar and Leesberg, also used to send him material. It is of further interest that van Hasselt has been in regular contact with Blackwall, Thorell, and Simon, important contemporary araneologists. Van Hasselt started to publish the results of his intensive collecting in the Tijdschrift voor Entomologie, as reports of his excursions; later, in 1885 and 1886, he composed a Catalogue of spiders collected in the Netherlands, which can be found in the same periodical. It was followed by three supplements in the years 1886, 1890, and 1898. The Catalogue and the supplements have also been issued separately; they must be regarded as reprints, only differing from the original by the numbering of the pages. The reprinted Catalogue, together with the first supplement appeared in 1886 (below it is referred to as sep. I), the reprinted second supplement (sep. II) and the third (sep. III) in 1890 and 1898 respectively. In the present paper I cite the Tijdschrift voor Entomologie, followed in brackets by a reference to the reprint. Van Hasselt preserved only a small number of specimens of each species, males and females in different tubes, without any reference on the label to the locality, except the origin from the Netherlands; consequently the number of records sometimes exceeds the number of specimens in the collection. In the cases of false or partly false identifications by van Hasselt, the localities