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The distribution, in time and space, of adult Aedes atlanticus, A. tormentor and associated woodland mosquito species was studied by use of light traps and man-biting collections. Peak abundance of adults of A. atlanticus, A. tormentor, A. fulvus pallens, Psorophora firox, P. Iongipalpis and P. ciliata occurred in spring and fall. Excluding midwinter months, these were the only 2 times that temporary pools were flooded. Greatest numbers of A. atlanticus and P. ciliata were collected in CDC light traps in an old field adjoining a woodland area; populations of A. infirmatus and P. longiPalpis were collected in more or less equal numbers in both woodland and field habitats. Other species, A. tormentor, A. fulvus pallens, A. triseriatlls and P. ferox , were abundant only in the woodland area. Diurnal hostseeking activity patterns were studied by a continuous 14-hr man-biting collection and a systematized 5-day series of 15-min. man-biting collections in 3 habitats: woodland area, woodland edge and old field. A crepuscular pattern was detected for A. atlanticus and A. tomentor , whereas P. ferox and P. longiPalpis were most active during midday. Host-seeking activities of A. tormentor and P. firox were greatest in the woodland area. Psorophora longipalpis was most active in the old field in early afternoon. Although A. atlanticus fed avidly in the woodland during the afternoon, most intense activity occurred in the field at sunset and gradually decreased after dark. Observations on the “depletion phenomenon” (the exponential decrease in attack rate with host exposure time) revealed that A. atlanticus and A. tormentor responded more quickly to a host during periods of peak activity than at other times. This was not observed for the attack rate of P. firox . Additional observations are reported on the depletion effect by species, habitat and time of collection. Findings are discussedin respect to the epidemiologyof Keystone virus.

The absorption and c.d. spectra of calycanthine and caracurine-II have been extended to 53 kK, and the π→π* transition energies and dipole and rotational strengths of the two alkaloids have been calculated in the π-SCF approximation using the dipole-velocity procedure. Theoretical absorption and c.d. spectra have been obtained for the alkaloids from the calculated quantities with a curve-plotter using a Gaussian band-shape function. The spectra computed for the previously assigned configurations of the two alkaloids reproduce the qualitative form of the experimental curves with magnitudes of the correct order. The π-SCF calculations are found to support the general features of the point–dipole exciton treatment of the electronic states and stereochemical configuration of chiral dimeric π-systems in cases where the latter method is applicable, e.g. calycanthine, but the former method is of wider scope and covers cases, e.g. caracurine-II where the latter fails.

High population densities of 2 dytiscid beetles, Laccophilus fasciatus Aube and L. maculosus Say, occur in some waste-oxidation lagoons in Missouri. These lagoons provide optimal conditions for reproduction to certain dipterous pests, notably mosquitoes and midges. In laboratory studies, adults of both dytiscid species were very active and voracious predators on the immature stages (especially the younger instars) of Culex pipiens L., and Glyptotendipes barbipes (Staeger). Mosquito pupae were less often attacked than larvae. G. barbipes were subject to predation before and during tube construction, when larvae left the tubes, and, as pupae, when they migrated to the water surface for adult emergence. The 2 Laccophilus species differed little in their predaceous capacities, and no difference was found between the sexes of either. Predation occurred to some extent under greatly reduced illumination.

The mechanical cycling test was required to verify the integrity of the welded joints and the thin wall tube bends in the primary loop manifold assembly of a four pack thermo electric module and to help establish structural and mechanical requirements of any possible redesign. The test section was subjected to more severe loading conditions than will be experienced during actual operating conditions. The test was a mechanical simulation of the differential thermal expansion which occurs due to the approximately 600{degrees} F temperature differential in the subassembly. The actual load exerted on the test section represented this deflection. The effects on the joints and tube material were observed. The test was conducted on a test segment of manifold designed to duplicate two of the flexible elbows; the transition joints between the elbows and the tubular module inner clad; and the welded joints of the elbows to the primary loop header. The assembled test segment and hold-down bracket are shown. The bracket was mounted to the base of the Universal Test Machine. Dial indicators measured the relative displacement between the line of applied load (through the vertical axis of the primary loop header) and the attachment point at the holddown bracket.more » In the first test, the load was applied in fifty pound increments until the relative displacement of nine mils was measured between the loop header and the welded joint on the feedline elbow. The remaining tests were cycling the header assembly at increasing relative displace ment. The summary of these tests are tabulated. The testing had no noticeable affect on the structural integrity of the weldment.« less