Do you know if the word "mechapede" has an other meaning than "robot millipede"?
I couldn't find it with online dictionaries. It's for this song : http://lyricstranslate.com/fr/abney-park-secret-life-dr-calgori-lyrics.html
Actually "robot millipede" could maybe work, but I don't know, I think it's a bit strange ^^"
It does mean that, and the context makes it plausible. The three previous lines
Test-tubes and Tesla coils,
Clockwork brain and glowing oils,
Copper, brass, explosive jelly
describe the technical nature of the "mechapede". The overall context of steampunk also makes it a good fit.
Since such invented portmanteau words have a potentially large variety of meanings, "mechapede" could describe any steampunk-y mechanical animal-like transportation device (or weapon), like a mechanical spider, a robot with several large or many small legs etc.
(sorry, I had forgotten this topic :S )
Thank you so much for your explanations! 
Actually I hadn't really understood the beginning of the song. You improved my English and steampunk knowledge 
