The image of a bee used in the logo for the "Global Implications of Colony Collapse (Disorder)" is a bumble bee; Colony Collapse Disorder is a malady that affects only honey bees (although declining populations of bees other than Apis mellifera are problematic they are not the result of CCD). (BTW, although dictionaries often prefer the spellings "bumblebee" and "honeybee" entomologists generally split each term into "bumble bee" and "honey bee".)
In the opening, Holmes confronts Hugo, an accused killer, with evidence left by the "serrated edge" of the Ka-Bar military knife he used in the crime. Ka-Bar combat knives have a single-edged non-serrated blade.
At one point Sherlock says the phrase "centers around." Sherlock is a master of both logic and language. He would know that something can "center on" or "revolve around" and would never say "centers around."
(Many episodes have Sherlock saying things that a language snob would never say.)
(Many episodes have Sherlock saying things that a language snob would never say.)