A population of praying mantids Mantis religiosa L. was studied in a submontane habitat near Vicenza in Northern Italy. Sixtythree mantids were observed and studied in the field with the mark and recapture method to obtain ecological information about the coloration patterns, habitat preferences and strategies of this species. Additionally, a population of mantids was housed in artificial conditions to estimate the presence of colour changes in adults. A regular distribution of the coloration of the insects was found in the field during the changing of the season, and partial colour changes not linked to the substrate or the moult process were observed in artificial conditions. The basic structure of the preferred habitat of M. religiosa is described as a pattern of grassland and thorny bushes of the Rosaceae family