They have species names like vexans and perturbans, though they weigh, unfed, a milligram or so. During the drought, their eggs have been waiting in the mud. Now with the rain and storms, they are out for blood.
Mosquitoes are celebrating the arrival of wet weather by taking to the air in squadrons of Aedes, Anopheles and Culex, experts said yesterday, departing with empty stomachs from salt marshes, tree holes and drainage ditches all over the area.
In Southern Maryland, so many nasty, long-range Aedes sollicitans have emerged from the salt marshes that state mosquito control officers have recorded "landing rates" on a person of up to 100 a minute.
Landing rates of 10 to 15 a minute are considered highly unpleasant, state officials said.
"We have had over the course of the last week a major outbreak of that mosquito on the lower Eastern Shore," Cyrus R. Lesser, chief of the Maryland Department of Agriculture's mosquito control section, said yesterday.
The salt marsh mosquito is known for its long flying range, at times more than 10 miles; large size; aggressive biting; and ability to carry the deadly disease eastern equine encephalitis.
Late yesterday, Maryland was scheduled to start combating the mosquito outbreak with an air assault of its own -- spraying 20,000 acres of marshland with the insecticide naled, according to Lesser.
But other kinds of mosquitoes -- Maryland has 58 versions -- are probably on the way, as the weekend deluges provide breeding grounds aplenty for baby critters that are expected to emerge as adults in five to 10 days.
"They lay their eggs in wet places above the water lines," said Duane J. Gubler, director of the division of vector-borne infectious diseases at the Centers for Disease Control and Prevention.
"The eggs go into a state of latency until it rains again and a brood of mosquitoes" hatches, he said. "That's why it's not uncommon to see, after a week or two of rain, hordes of mosquitoes."
Or as a worker at the Virginia Beach mosquito control commission said yesterday, "Give it about a week or so, and we're going to be busy."
So far, local officials said yesterday, there have been no reports of mosquito-borne human disease, as there have been in New York City. An outbreak of St. Louis encephalitis, probably carried to the area by an infected bird, has killed two people there and sickened as many as 37.
Neither Maryland nor Virginia has seen any human encephalitis in more than a year, officials said. District health officials could not be reached yesterday.
Surprisingly, the Culex pipiens mosquito that carries the St. Louis encephalitis, which officials said has a fatality rate of 10 percent or less, thrives in drought conditions, breeding in places like septic tanks, rain gutters and storm drains filled with decaying leaves, Gubler said.
But the salt marsh mosquito carries the more deadly eastern equine encephalitis, which Lesser said has a fatality rate of 50 percent. A Portsmouth, Va., man died of eastern equine encephalitis last year, a state health department spokesman said yesterday.
Lesser, the Maryland expert, said none of the mosquitoes that have been checked for disease this summer have been infected with any human encephalitis, though a risk remains because of the higher insect numbers.
The area already was under attack by a potent newcomer, the Asian tiger mosquito, known for its daylight urban raids, voracious appetite and black and white markings.
Then came reinforcements from the salt marsh.
"Trying to control the Asian tiger is like trying to fight guerrilla jungle warfare," Lesser said. "It's always hit-and-run. . . . The salt marsh mosquito is more like a Napoleonic frontal assault."
Lesser said the proliferation of the salt marsh mosquito is a direct result of low water in the marshes, which left much larger areas for the female insects to deposit their eggs.
"These eggs have the amazing ability to withstand long periods in dry conditions," he said, "weeks and months and, in extreme cases, years at a time."
The recent storms and higher tides pushed water into the marshes, triggering the hatches, he said.
There are, however, things the public can do to fight mosquito infestations: Cover up when going outside. Use insect repellents. And use what Gubler said was perhaps the best defense:
"Stay indoors and watch television in air-conditioned living rooms in the evening."