X chromosome

On a random tree in the woods, when I was looking for fungi or moss to photohraph, I found this (see extra for what it looked like): A group of red firebugs overwintering. Apparently this is a very gregarious insect, and it does make sense to stay close to keep warm through the cold months, problem is that sometimes it does so in our homes and become a pest. I miss reading up on the insects I see through my macrolens so I grabbed this opportunity to learn something new. What I found out was that in 1891 the german biologist Hermann Henking was studying the testicles of firebugs (who wouldn't want to) when he noticed that during meiosis an element (which he called element X) did not divide like all pairs of homologous chromosomes but was transmitted directly to the daughter cells. So next time that you see a red firebug (and maybe chase it out of your house where it decided to overwinter) remember that it was fundamental for the discovery of the chromosomes that determine sex in all living species!