If mail then tumblr

1
Connect

if #tumblr in you email post on tumblr

If

Email icon
Send IFTTT an email tagged

Send IFTTT an email at trigger@applet.ifttt.com with a hashtag in the subject (e.g. #IFTTT) and this Trigger fires. You can optionally add a single file attachment (up to 30MB) and IFTTT will create a public URL to the file as an Ingredient.

Then

Tumblr (legacy) icon
Create a text post

This Action will create a text post on your Tumblr blog.

Fewer details

Discover more time saving integrations for Tumblr (legacy) and Email