Investment losses pulled down profit at Arlington-based USLICO Corp. in the third quarter, the company said.

The insurance company's net income fell 3.7 percent to $7.7 million (64 cents a share fully diluted) from $8 million (70 cents) in the third quarter last year.

Revenue was up 8.2 percent to $116.1 million from $107.3 million.

The company said the income drop-off came because of a capital loss of $100,000 on investments, compared with a gain of $600,000 in last year's quarter. All this year, USLICO's investments have proven less profitable than in the past -- in the first nine months, capital gains came to $400,000, compared with $5 million in the first nine months of 1989.

The company said that its investments in one of the hardest-hit market sectors -- high-risk, high-yield junk bonds -- account for 2 percent of its portfolio, less than the industry average.

Among its operating divisions, USLICO said, life insurance has been growing the most strongly.

CACI International Inc., an Arlington software company, blamed an uncertain market for a 19 percent drop in profit in the quarter ended Sept. 30.

CACI's net income for the quarter was $677,329 (6 cents a share) compared with $837,150 (7 cents) a year earlier. Revenue in the quarter was up 3 percent, to $35.6 million from $34.6 million.

"Along with virtually all our business colleagues in the information systems and software products industry, we are seeing a soft buyer market with tighter margins and a 'wait and see' approach due to U.S. government budget uncertainty," said J.P. London, the company's chief executive.

Danaher Corp., a Washington holding company for various manufacturing businesses, earned $11.8 million in the quarter ended Sept. 30, up 10.5 percent from $10.7 million a year earlier.

Because there is more stock outstanding now than a year ago, that's the equivalent of 40 cents a share compared with 45 cents a share in the 1989 quarter.

Revenue in the period was up 24.8 percent to $229.9 million from $184.2 million.