Vietnam blue

[Wolfram1]

Don't know about the Color Blue however in the Name as it is completely Brown?

so none of the spiders actually have blue pigments in their exoskeleton, its all about the molecular structures of their pubescence and setae and how light is reflected, so freshly molted adults under a bright cold white light appear blue, when their actual colours are shades of brown

 

[MariaLewisia]

Might be a bit superfluous for me to join the discussion and regurgitate the same old, but still, I have to agree with everyone else. Just leave it to do its thing. Fossorials, aka "pet holes", regularly close up shop for long periods of time, premoult or not, and that's just something you have to wait out. They know what they're doing. I barely ever saw my oldest Hysterocrates gigas during the two years she had all of her tunnels in the middle of the enclosure. She just flashed a toe or two when she got hungry, then closed the opening some months later to be left alone until she moulted or got hungry again. Rinse and repeat. Last year she finally expanded the tunnels to the sides of the enclosure and now I can actually see her. My C. dyscolus "Blue" is the same, although she's slightly more prone to go outside. But only slightly.

so none of the spiders actually have blue pigments in their exoskeleton, its all about the molecular structures of their pubescence and setae and how light is reflected, so freshly molted adults under a bright cold white light appear blue, when their actual colours are shades of brown

It's not as bright as the newly moulted spider, but you can still see some lovely blues on old moults at the right angles and with flash. This was from my large juvenile/semi-adult C. dyscolus "Blue". It's so neat to see them go from brown spiderlings to more and more blue adults every subsequent moult.

 

[Brewser]

Charliemum has information that's worth paying attention to..