Seven kinds of people you find in bookshops

Genus: peritus (expert)

Genus: familia juvenisis (young family)

Genus: homo qui maleficus amat (occultist)

Genus: homo qui desidet (loiterer)

Genus: senex cum barba (bearded pensioner)

Genus: viator non tacitus (the not-so-silent traveller)

Genus: parentum historiae studiosus (family historian)

Bonus

Genus: operarii (staff).