katisu, here are some keys to asters (or similar identification aids). I've arranged them by nearness to your location. Chicago region; photo-collection with description: http://fm2.fieldmuseum.org/plantguides/guide_pdfs/505%20aster%20of%20Chicago.pdf Wisconsin; key [I assume you'd want Tribe 6, and don't know if any of the other tribes are likely or even possible]: http://wisplants.uwsp.edu/composites/ Ottawa region; key: http://www.ofnc.ca/fletcher/flora-fauna/keys/asters/ Ottawa; most common asters; list with main points, also links: http://ontariowildflowers.com/groups/1/asteridsummary.php New England; essentially a key: https://gobotany.newenglandwild.org/simple/non-monocots/composites/#_filters=family,genus,habitat_general,state_distribution,leaf_type_general_co,leaf_arrangement_co,leaf_blade_margin_co,capitulum_form_co,ray_flower_color_co,pappus_general_co&_view=photos&_show=flowers

They could come in if you are seeing many, to find places to lay eggs (ie, your woolens if not well stored). Look for them on windowsills and inside overhead lights, if you have the kinds with open glass shades that cover bulbs. That will give you an idea if they are using the house as a breeding ground. I watch the lights for them, actually, as I do not want a repeat of what I went thru before. I saw my first one last week. I store everything in spacebags now, as mothballs will only kill the larve if they are sealed inside closed boxes w/ no way out to hold the gasses. I am not sure what they mean for your roses and can't remember if/what their predatory bugs are, but know that they will destroy any woolens, leather, and any protein fibers quite thoroughly. They can be very hard to get rid of if they take hold inside.

Can't really see much from the image. Is your lychee in a container or in the ground?

https://www.youtube.com/watch?v=wMNdnQZGoqo This looks similar. I have no means of magnification yet so I can't say for sure. If I did, I wouldn't be here lol. I just want a "this is what typically exists" type answer.