The rostral tip of the tarnished plant bug contains two sensory fields each containing eleven sensilla basiconica. Removal of the rostral tip or antennae abolishes a feeding preference for frego bract cotton squares, suggesting that receptors at these loci are essential for a normal behavioral choice. Electrical recordings from the rostral nerve show increased impulse activity to stimulation of the rostral tip sensilla with juice from frego bract and normal bract squares of three varieties of cotton, confirming their function as contact chemoreceptors. Histograms of impulse frequency against time exhibit differences among the three cotton varieties tested.Although more than 70 species of Heteroptera are known to bear sensilla on the apex of the rostrum, there is no unanimity in the literature concerning their functioning (Cobben, 1978). Contact of the labial tip with the substrate is one of the first behavioral events of host recognition in Oncopeltus faseiatus and seems to provide information important for further feeding (Beck et al., 1958;Feir & Beck, 1963; Bongers, 1969). Although Frings & Frings (1949)concluded that there were contact chemoreceptors at the labial tip, since stimulation of these with sucrose resulted in ingestion of the solution, it was later pointed out by Miles (1958) that it was also possible for a test ingestion to occur, resulting in fluid contact with epipharyngeal chemoreceptors which in turn resulted in ingestion.The rostral sensilla in Dysdercusfulfonige'r and Dysdercus koenigii were shown by Schoonhoven and Henstra (1972) to consist of 24 sensilla basi,conica and two sensilla trichodea arranged in two sensory fields. Ultrastructurally the sensilla basiconica of these species and of D.fasciatus (Peregrine, 1972a) resembled contact chemoreceptors and preliminary electrophysiological studies by Schoonhoven and Henstra (t972) also supported a chemosensory role. Hansen et al. (1976) cite data of Bresch (1973) showing electrophysiological responses of the labial hairs of the cotton stainer Dysdercus to a wide variety of sugars.Behavioral observations of Dysdereus and Oncopeltus reveal that while the labial tip is being tapped against the substrate, a watery saliva is often discharged and sucked back through the stylets (Miles, 1958; Saxena, 1963). Thus, during the contact of the labial tip with a plant surface, both rostral and epipharyngeal

The interaction of clouds and radiation is a particularly difficult issue in the study of climate change. Clouds have a large impact on the earth's radiation budget but the range of spatial and temporal scales and the complexity of the physical processes associated with clouds made these interactions difficult to simulate. The Department of Energy's Atmospheric Radiation Measurement (ARM) program was established to improve the understanding of the interaction of radiation with the atmosphere with a particular emphasis on the effects of clouds. To continue its role of providing data for the study of these interactions, the ARM program deployed an Atmospheric Radiation and Cloud Station (ARCS) in the tropical western Pacific. This site began operation in October 1996. The tropical western Pacific is a very important climatic region. It is characterized by strong solar heating, high water vapor concentrations, and active convection. The ARCS is equipped with a comprehensive suite of instruments for measuring surface radiation fluxes and properties of the atmospheric state and is intended to operate for the next 10 years. The ARCS is an integrated unit that includes a data management system, a site monitor and control system, an external communications system, redundant electrical power systems, and containers that provide shelter for the equipment as well as work space for site operators, technicians, and visiting scientists. The dataset the ARCS produces will be invaluable in studying issues related to clouds and radiation in the Tropics. The site is located in Manus Province, Papua New Guinea, at 2.060°S, 147.425°E, 300 km north of the island of New Guinea. Two more ARCS are planned for deployment across the tropical Pacific.

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