Why Won't My iPhone Lightroom Photos Stay On My Hardrive?

With my iphone plugged into my iMac, I can see and drag the Lightroom folder from my iPhone into my iMac hard drive.

However, it only stays for a few seconds on my iMac before it disappears off the hard drive. 

I know the Apple file system is a little bit closed, but is there a way to get just the Lighroom files off the phone without having to use big Lightroom and sort through all the other photos on my phone?