B. butteli is closely similar to B. ecuadorius. B. ecuadorius females are very rare in collections. This putative male of B. ecuadorius also differs from the females in having yellow hairs intermixed on the front and rear of the thorax. Currently I favour another possible interpretation. This might explain the difference in colour pattern and distribution from other B. ecuadorius .
Further evidence is awaited.
W Neotropical Region. B. robustus and B. hortulanus are morphologically similar. I hairless, and the space between the inner processes of the male gonostylus is wider than the breadth of the apical process. Until more evidence to the contrary is available from critical studies of patterns of variation, I shall treat them as separate species. W Neotropical Region.