"I have been spending a number of years studying parasitic insects," said Professor C. T. Brues, assistant professor of Economic Entomology to a Crimson reporter last night, "and it is to help carry on this work that I applied for the Milton Award which I was granted two or three weeks ago."

The reporter had gone to interview Professor Brues at his home in Forest Hills, and there sitting in the living room before an open fire which was roaring in the grate, Professor Brues outlined the work which, up to the present, he has been doing.

Insects Prey On Insects

"There is a class of insects," he said, "which are parasitic upon other insects; a rather rare occurrence in the animal world, by the way. As a rule one group of animals is parasitic upon some totally different group, as for insects on mammals. In this case, however, a class of insects is parasitic upon another class of insects. The economic importance of this fact is well known. Where insects are introduced into a foreign country they often prove very destructive because there are usually in that country no parasites to prey on them. This, you know, was the case of the Gypsy Moth. This month was introduced from Europe, and has wreaked great havoc upon the trees here in the east.

"Some time ago about a dozen species of insects parasitic upon it, were imported and established, and since that time they have done much to decrease the number of Gypsy Moths. Of course the moths can never be entirely exterminated in this way, but eventually, since the parasites increase generation after generation up to a certain point, a balance is reached and a natural control of the insect pest is brought about.

"The work in this field," continued Professor Brues, "which I have been doing for the last years has however, been connected more with the study of the fossils of these parasitic insects rather than of the existing insects themselves, although work on them came in too. We know something of how the world has been populated in geological times but our knowledge until recent years has been principally confined to the large animals, the reptiles and mammals.

During the Tertiary age which is the most recent geological period before the present many parasitic, insects similar to those existing now abounded. By studying these and comparing them with existing species we can learn something of their relations and migrations from one area to another.

Tsetse Fly Lived in America

"An interesting phenomenon with this study by fossils of the migrations of insects, is that there is evidence that the Tsetse fly which acts as a host for the gums which give sleeping sickness, and is at present restricted to Africa once existed in America and may have had something to do with the disappearance of the large mammals here."

Just how the parasitic insects were preserved in a fossil state so that they could be studied advantageously was not clear to the reporter until, in reply to his question, Professor Brues said that there were large numbers of insect fossils in Baltic amber.

Insects Caught in Gum

"This amber is the fossilized resin of great pine trees which grew in northern Europe during the early Tertiary period. Naturally, insects just as at present were entangled and covered by the gum, large numbers of them being contained in it when it became fossilized. It is remarkable how excellently these insects are preserved in the amber. Some, of course, are disfigured from one cause or another but many are quite natural in appearance and can be fairly easily studied in the relatively clear material.

"An interesting thing was discovered some time ago," Professor Brues continued, "when in one piece of amber was found a spider and in another the remains of an insect which had obviously been entangled in a spider's web and eaten, these animals of three to ten million years ago showing habits remarkably similar to those of to-day.

"The fossil-bearing is amber occurs in several places, but is particularly abundant around the Baltic sea. Much of the land originally covered by the great pine forests has at present sunk into the sea, and lumps of the amber are constantly being cast up on the Baltic beaches. The lumps of amber are then sliced and polished so that the insects imbedded in it are brought as near to the surface as possible. Most of the fossil-bearing amber available for study," said Professor Brues, "is contained into the various museums of Prussia."

Professor Brues will continue his studies with the help of the Milton Award during the coming year.