Folia Historico-Naturalia Musei Matraensis - A Mátra Múzeum Természetrajzi Közleményei 21. (1996)

compared to its length is greatest in the Red-footed Falcon, and smallest in the Merlin. In this respect the order of the species is the following: F. vespertinus = F. naumanni > F. subbuteo = F. tinnunculus > F. columbarius The downward curving of the symphysial part (lateral view) is strongest in the Merlin, is more curved, and the curving is most flattened in the Hobby (Plate XXXV, Figures 15-17). The fenestra mandibulae rostralis and the fen. mand. caudalis are both present in all of the species, very occasionally closed in some Hobby and Merlin individuals. The fenestra mandibulae rostralis is the most opened and biggest in the Red-footed Falcon. The surface of the pars caudalis of ramus mandibulae (os articulare) is largest in the Kestrel, and in the Hobby is relatively smaller than in the Merlin (dorsal view). The shape of the caudal part is also different in the discussed species (Plate XXXV, Figures 18-21). The processus mandibulae medialis is longest in the Kestrel, but in the Red-footed Falcon curves downward stronger in dorsal direction (caudal view) than in the other species (Plate XXXV, Figures 5-6). In the Falcons the processus retroarticularis is very small, or hardly detectable, but on the dorso-medial edge of fossa caudalis there is an another, dorso-caudal protrusion (later referred to as prominentia caudalis). This protrusion is more pointed in the Merlin and Red-footed Falcon, and bigger in caudal direction than in the Hobby, Kestrel and Lesser Kestrel (Plate XXXV, Figures 18-21). The processus retroarticularis is very small but visible in the Red-footed Falcon, and practically missing in the Kestrel. Summary Falco subbuteo: - the ramus mandibulae at the symphysial part is curved downward in a flattened arch (lateral view), - the surface of the pars caudalis of ramus mandibulae is relatively the lowest (dorsal view), - the tip of prominentia caudalis is small and rounded, blunt (dorsal view). Falco columbarius: - the ramus mandibulae is the lowest, - the ramus mandibulae at the symphysial part is curved downward very strongly (lateral view), - the prominentia caudalis is big and pointed (dorsal view). Falco tinnunculus: - the spread of the rami mandibulae is strongest in this species, - the pars caudalis of ramus mandibulae is relatively large (dorsal view), - the processus mandibulae medialis is longest in this species, - the prominentia caudalis is small and rounded, blunt (dorsal view), - the processus retroarticularis is missing (lateral view). Falco vespertinus: - the ramus mandibulae is relatively high, - the fenestra mandibulae rostralis is most opened in this species, - the prominentia caudalis is big and pointed (dorsal view), - the processus retroarticularis is detectable (lateral view). Falco naumanni: - the ramus mandibulae is high, - the prominentia caudalis is small and rounded, blunt (dorsal view). 20