Simple Summary: Several members of the Cimicidae family are ectoparasites of vertebrates. Some of these are economically and medically important, e.g., the bed bugs, which are a global pest affecting humans. The development of a method to easily identify species of the Cimicidae family, despite the high morphological similarity of its members, will bring benefits such as the early detection of emerging infestations, facilitating the setup of adequate control and management measures. One of the existing methods, traditional morphometry (linear measurements and ratios of an object), is a demanding process involving the examination of many morphological features of well-preserved samples. An alternative approach that uses only one morphological feature could be an asset. Therefore, we assessed the use of a single organ, the pronotum, to classify Cimicidae via two methods: traditional and geometric morphometry (a method capturing the geometry of an object using coordinates as opposed to simple linear measurements and ratios). Both methods were effective in classifying members of the family based on the pronotum; however, better quality data were obtained with geometric morphometry. We recommend adopting the latter approach in future surveillance programs for medically important members and poultry pests of the family.