The slogan proclaims “Death to Traitors,” and next to it is a caricature of a man stomping on a Confederate flag.

A newspaper editorial cartoon from the Civil War? No. It is one of numerous envelopes bearing colorful prints that were used to mail letters in the North and the South during the Civil War.

Such envelopes were referred to as “patriotic covers,” with a patriotic bent toward either the Union or the Confederacy.

“This was the early standard of propaganda,” said Craig Sundell, a Lawrence paleontologist and Civil War history buff. “They were used by people during the Civil War like we use bumper stickers today.”

When Sundell, 51, isn’t digging up dinosaur bones somewhere in the western United States, he might be adding to his collection of Civil War artifacts, including the envelopes he began collecting only a few months ago. He has amassed a few hundred of them, which he keeps wrapped in plastic.

In addition to finding the envelope artwork fascinating, Sundell also sees them as telling the history of the War Between the States. One of his favorites is an envelope with a slogan that says simply, “Kansas Loyal to the Union.”

It is the only Kansas envelope Sundell has, although he knows there are more out there, including one he tried but failed to obtain over the popular online auction site eBay. The envelope had a letter in it from a Union Army surgeon who wrote about an attack on Humboldt, Sundell said. It sold for $250.

“They were advertising it as a ‘Bleeding Kansas’ letter,” Sundell said. “Anything that’s Bleeding Kansas is at the point now where it’s very popular.”

Envelopes from the Civil War that still have their accompanying letters carry a higher value, and those written by soldiers describing battles have the most value, Sundell said. He has only one such envelope, postmarked in St. Louis and containing a letter handwritten in German. He hopes to have it translated.

Craig Sundell collects Civil War covers, or envelopes, that were used to mail letters during the War Between the States. Such envelopes, which have been likened to bumper stickers of today, showed a patriotic bent toward either the Union or the Confederacy.

According to the Web site Stamps.net, patriotic covers range in value from $25 to more than $10,000. But many are cheap and can be had for only a few dollars, Sundell said. On eBay, there recently were several Civil War covers listed with bids ranging from a dollar to nearly $50.

Patriotic covers are popular among stamp collectors and others who are interested in philatelic items, said Ernie Angino, a member of the Lawrence Stamp Collectors Club.

“You know how popular the Civil War is now, and this is a part of it,” Angino said. “Nobody has any idea how many patriotic covers there are out there. It’s all part of postal history.”

Similar envelopes were used during other wars, including the Spanish-American War, World War I and especially World War II, Angino said.

“The bigger the war — the longer and nastier the war — the more they seemed to come out,” Angino said.

This Kansas-themed cover is the only one from this state that Craig Sundell has in his collection. Sundell says that Bleeding

Sundell would like to add some Confederate covers to his collection, but so far he has been unable to swing a deal for them. Confederate covers are scarcer and more closely held by those who have them.

“People with Confederate leanings tend to be, well, real Confederate,” Sundell said. “I actually have a guy in Virginia who doesn’t want to deal with me because I collect Union covers.”

Sundell traces his interest in the Civil War back to his childhood. A little more than a year ago he helped form the Lawrence Samuel Churchill Camp 4 of the Sons of Union Veterans of the Civil War, a group that meets monthly and sponsors programs about the war.