Colletes hederae-complex: Both sexes of C. succinctus resemble C. hederae in the field. However, there are some subtle differences in their average size, the width of their tergal bands and in the appearance of some internal structures (e.g. galea). These characters are hard to evaluate on living specimens and some can only be observed with optical aids (i.e. microscope). Whenever possible, the most straightforward way to separate these closely related Colletes species is by observing their foraging habits and host plants.

References: Amiet F, Müller A, Neumeyer R (1999) Fauna Helvetica 9. Apidae 2 : Colletes, Dufourea, Hylaeus, Nomia, Nomioides, Rhophitoides, Rophites, Sphecodes, Systropha. Centre Suisse de Cartographiede la Faune, Neuchatel, Switzerland, 219 pp.