I noticed a ton of my leaves being eaten and found quite a few of these but much smaller... two weeks later i find a huge one. I never had fly's before but about two weeks ago i had a ton of fly's in my grow room and im sure they brought in these catapillar looking things and spread around spider mites as well.. had to have been the fly's cause ive never had these catapillar looking things in any of my grow rooms and the first time ive had fly's as well.. what are they?