Louis M. Roth does not have to go looking all over the world for his specimens--they come to him, usually in an envelope. Roth, who is known in the field of entomology as the leading expert on cockroaches, frequently receives exotic insects in the mail with requests to identify them.

"In many cases I can recognize a species just by looking at the genitalia," says Roth, a research associate in the Museum of Comparative Zoology (MCZ). Roth says that he also looks at an organism's wings and the sexual glands of a male when attempting to place a specimen taxonomically.

The entomologist has been studying the behavior and taxonomy of numerous cockroach species for more than 40 years, the last six of which he has spent working on the fourth floor of the MCZ. Before coming to Harvard in 1982, Roth headed the Army's Entomology Research Group in Natick, where he pioneered many of the basic studies on the behavior of these insects, which have been in existance for more than 300 million years. One recent morning, Roth discussed his four decades with cockroaches, explaining his work and peppering his reminiscences with humorous anecdotes about his days with the army.

Lately, the mail has held quite a few specimens for Roth. Last year, the U.S. Department of Agriculture (USDA) sent him some cockroaches found in Florida, with a request for identification. He looked at the specimens and decided that they were German cockroaches, but the USDA wrote back, saying that the insect was not behaving like the German roach. Unlike this common species, these cockroaches are attracted to light and can fly.

Roth looked at the specimens again and decided that they might be Asian cockroaches, which had never before been seen in America. He sent the specimens to a Japanese entomologist who confirmed that it was indeed the species Roth suspected it to be. Roth and USDA officials speculate that this roach species was recently produced to America.

USDA officials say that Roth's work was instrumental in helping them decide how to approach the growing cockroach infestation problem in Florida. "[The Asian cockroach] has a present potential to be a pest problem, so [Roth's] work is very significant in defining the pest problem," says Richard Patterson, research leader at the USDA's division on insects affecting man and animals.

No Simple Task

Identifying a cockroach is no simple task. There are currently about 4000 described cockroach species, and Roth says he thinks there are "at least twice as many undescribed species." A biologist must determine that the organism has not previously been assigned to a species before he or she can say it is a new species. To ensure this, the entomologist must turn to detailed descriptions of the species prepared by his colleagues.

And for many insect researchers, Roth is often that colleague. Currently he is working on describing a species found on the Island of Krakatau, where the environment was destroyed by a volcanic eruption about 100 years ago. He suspects that the species now inhabiting the island emigrated from one of the neighboring islands, such as Java or Sumatra.

In fact, the Harvard entomologist has so many requests to identify species that he must turn some down. Recently, Roth had to decline an invitation to study some specimens found on an expedition conducted by the Russian Academy of Sciences--the same institution he wrote to several years ago asking for a specimen he was interested in studying. "We didn't have glasnost then, and I'm sure the minute they saw the U.S. Army letterhead...I never heard from the man," he says.

Roaches From Down Under

What has been occupying most of Roth's time these days is a much more extensive research project--the revision of an entire family of Australian cockroaches. The project is based out of the centerpiece of Roth's MCZ office, a cabinet about four-feet high with four compartments, each holding about 20 trays of pinned cockroach specimens. totaling about 6000 specimens.

"I doubt I'll ever finish it," he says of the study, which he began in 1982 at the behest of the Australian government. Roth currently examines pinned cockroaches, and if there is enough specimen, he prepares slides of the insect's glands to aid in classification of the various species.

"There are some species which are very, very similar and that have the same markings. If you just looked at these markings without studying the internal structures, you would assume they are all the same," he explains. "Some of them are striking. They may not look that way when you see them with the naked eye, but under the scope..." he adds.

Roth, who received his Ph.D. in insect physiology in 1946, is the specialist to whom biologists turn most frequently for information on cockroaches. "He's probably the foremost cockroach taxonomist. He has a world-renowned reputation. He's a very brilliant and helpful individual," Patterson says.