Thank you for your question. Your comparison with Asian lady bugs is close. Are you seeing damage on your tiger lilies? It is difficult to see the markings on the bug but it appears to be either a signate lady beetle or a twice stabbed lady beetle. Neither will harm the tiger lilies. These beetles are considered beneficial insects because they eat scale and other smaller insects that harm plants. It could also be a variant of the Asian lady beetle called harlequin. Does it stink when you squash it? If not it is probably one of the above. You may be able to come up with a closer identification from the links below. http://bugguide.net/index.php?q=search&keys=Lady+beetles&search=Search http://www.insectidentification.org/beetles.asp

Another possibility may be a stink bug nymph.
http://www.omafra.gov.on.ca/IPM/english/tomatoes/insects/stink-bug.html
Spray your lilies with a garden insecticide, such as carbaryl (Sevin) or permethrin. Stink bugs are relatively tolerant to many insecticides making suppression difficult.

Here is Another stink bug nymph image from Minnesota Department of AG. Stink bugs are usually more interested in trees especially fruit trees. Be sure to correctly identify the insect before treating your lilies. If it is a stink bug you will want to treat because they can invade homes. If it is not a stink bug you may kill beneficials and have an infestation of aphids or other pests. If you send a better closeup we may be able to be of more help. Again if it stinks it is probably a stink bug or Asian lady bug. http://www.mda.state.mn.us/plants/insects/~/media/Images/plants/insects/bmsb/bmsbeggs.jpg http://www.mda.state.mn.us/plants/insects/stinkbug.aspx