The MUSE - Science Museum of Trento (formerly Museo Tridentino di Scienze Naturali) is an Italian regional museum founded in 1922. The natural history and archaeological collections of the museum (297 collections and 5.5 million objects) are of great interest for their close relationship with the Alpine Region. The oldest materials were collected more than two centuries ago and the collections increase every year through many new acquisitions. Invertebrate collections of the MUSE include more than 1.2 million specimens, aquatic and terrestrial, 70% of which are of local origin. Historical collections (1850-1950) include mainly terrestrial insects.

Odonata account for a minor part of the "Miscellanea Invertebrati" collection (cINV017), with 954 specimens collected since 1924, mostly in Trentino (NE-Italy). The bulk of the collection (836 specimens) was created between 1924 and 1957 and is referred hereafter as the 'historical collection of dragonflies of the Science Museum (MUSE) of Trento'. The remaining samples refer to 2009 and were collected at two sites of Trentino in the framework of a specific project, the results from which have already been reported in Lampo et al. (2011). Hence, this contribution intends to present the catalogue of the historical bulk of the collection.

The dragonflies in the Museo Tridentino di Scienze Naturali collection were previously studied by Cesare Nielsen in 1932, who reported the available records at that time (which were a small number compared to the ones available today) (Nielsen 1932). They were subsequently studied by Cesare Conci and Osvaldo Galvagni in 1944, who only reported several relevant data for an individual species, Sympecma paedisca (Brauer, 1882) (Conci and Galvagni 1944).

This considered, we think it important to publish the full catalogue of the historical collection of dragonflies of the Science Museum of Trento, since these data represent the first organic and verifiable bulk of knowledge on the Odonata of Trentino. In fact, apart from two 19^th century very general and not verifiable studies (Ambrosi 1851, Ausserer 1869), no other previous information exists which allow the delineation of the past odonate fauna of this area. Additionally, during the 34 years to which the records in this collection refer, few data on the Odonata of Trentino were published and most of them referred only to scarce species (i.e. apart from those already cited: Morton 1926, Conci and Galvagni 1946, Conci 1957, Conci 1948, Morton 1928, Marcuzzi 1948).

Historical data from the Natural Science Museum collections allow comparisons with present animal assemblages and enable the understanding of the dynamics of the communities (i.e. species extinctions and colonisations) and concurrently of ecosystems (Regneire et al. 2015). These modifications could be the result of natural processes or, more often, of the anthropogenic impacts on biodiversity; thus, collection data play a fundamental role in documenting environmental changes (Schmitt et al. 2018). This also explains their invaluable importance in planning conservation and management actions (Remsen 1995, Gobbi et al. 2012). As an example, of the 61 odonate species recorded in Trentino, four (Sympecma paedisca, Lestes barbarus, Coenagrion scitulum and Brachytron pratense) were not reported after 1950 (Assandri, unpublished data). For all of them, at least one sample is conserved in the historical collection of dragonflies of the MUSE, confirming their indisputable former occurrence in that region.

We would like to thank Maria Chiara Deflorian for her valuable help on the definition of the collection catalogue codes and the Pensoft staff for its assistance on technical issues related to the creation of this paper.

GA and VL conceived the idea; GA revised the collection with the support of AF; GA created the collection database, analysed the data and wrote a first draft of the paper; VL supervised as chief-curator of the entomology department of the MUSE the research development and acquired funding for publication; all authors contributed critically to the drafts and gave final approval for publication.