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A mathematical model has been developed for estimating the consumption of canopy vegetation by insects. The model divides canopy leaves into age classes according to time of leaf emergence. Periodic measurements were made of gross leaf area and hole area initiated by insect consumption for each generation. Gross area distributions were used to determine empirical growth functions for the canopy vegetation. The rate of change in hole area is a function of both insect consumption and subsequent hole expansion due to leaf growth. The hole expansion rate was determined empirically by punching holes in known area in growing leaves and correlating hole expansion with leaf growth. From these relationships, a linear differential equation was derived to describe the dynamics of insect grazing in the canopy. This model was used to interpret the effect of insect herbivory on the dry matter and nutrient cycles in a Liriodendron tulipifera forest. Average herbivorous insect consumption over 3 years was equivalent to 2.6% of the net primary production of foliage biomass but represented an annual loss of 7.7% in photosynthetic surface area.

IN the design of aircraft structures for fatigue strength, it is as well to bear in mind that those parts most likely to give trouble fatigue‐wise are those wherein rivets or bolts have to react a load. The term ‘react’ is used here to distinguish this from the case where rivets or bolts arc used to hold the skin on the frame, etc., where the worst possible concentration of stress in terms of the nominal gross area will approach that of a hole in an infinitely wide sheet, or about 3·0. The riveted joint is more likely to approach that of a lug, which, for conventional rivet spacing and edge distance would be about 5½ in terms of gross stress. In other words, our working stress for a joint would be about one‐half the axial stress in a plain sheet with holes for the same life. Other things, such as normal loads and buckling, may alter this ratio somewhat.

The purpose of this paper is to bring before the Association the application of the newer and more scientific methods of field control of concrete to the construction of an important water works structure. The writer hopes it will prove of interest to the society and a benefit to those engaged in concrete work, particularly in water works structures. This reservoir was constructed in 1926 at the Fall Creek Station of the Indianapolis Water Company by the local organization of the Thompson-Binger Co. of New York, General Contractors. It occupies a space approximately 270 feet square and has a gross area of over 60,000 square feet, with an overall depth of 16 feet, and a storage capacity of 6 million gallons. The roof is a flat slab, 8 inches thick supported by circular columns, 20 inches in diameter, spaced 16 feet centers and resting upon a groined-arch floor having a minimum thickness of 8 inches. Local ground water conditions made necessary the provision that the structure and its loading should have weight sufficient to balance an upward pressure of ground water at flood times with the reservoir nearly empty, hence the groined arch floor design. Incidentally, the arched floor forms valleys which permit easy cleaning.

The economics of research animal production run the entire gamut from production to utilization and embrace management, distribution and financing. Since others at the Symposium have already spoken on transportation and distribution problems, the management of animal facilities, supply, demand and the raising of animals and operational methodology, the comments herein will be confined to the financial considerations inherent in the breeding of experimental animals. This paper will concern itself primarily with the costs for animal production incurred in the USA. First consideration must be given to the land on which production buildings are to be placed. In addition to the thought given to legal problems of usage and water supply and drainage, distance from markets, availability of labour and nearness of transport, one must also keep in mind the initial value of the land. More and more, the accessibility of land for animal production facilities and its cost are becoming inversely related to the distance from major cities. Because of the expensiveness of tracts of ground in or near large cities, it is frequently necessary to compensate for this cost by constructing high, multi-storey buildings which are not widely regarded as good animal production quarters. The alternative, then, is to build a one-story building (with or without a basement), spreading it out, as need dictates, over a large area of ground. This design will keep down the original expense for the land and, at the same time, provide a suitable structure for this purpose. In addition, one must take into account landscaping and tree planting, both for aesthetic reasons and in order to dampen sound. Although the facility for the housing of laboratory animals in a production colony will account for the greatest portion of the original expense, it is extremely difficult to provide cost figures since such variables as materials, labour and design change with bewildering rapidity as you travel from country to country and from one geographic area to another. The National Institutes of Health has recently renovated a building constructed in 1956 for animal breeding. Built as part of their conventional animal facilities in 1956 at a cost of $21/ft 2, it was not used as animal space, but provided temporary office accommodation for personnel until now. If, rather than being planned for conventional animals, it had been built to specifications for specific pathogen-free animals, it would have cost $25/ft 2 in 1956. In 1963, the estimated cost, a combination of original construction prices plus the addition of equipment, such as special air-conditioning and electrically interlocking doors, had risen to $32/ft'-', an increase in 7 yr of $7/ft '. The figures given are for gross area (R. S. Runkle, personal communication). Another government research institution has recently erected a series of 3-room animal buildings, completely air-conditioned. The cost was $26/ft '. Phillips (1963) has estimated the cost of infectious disease laboratories with attendant animal housing facilities at

Floor area and population data from three geographical areas are given. The value of recording the use of each floor area is demonstrated. Because of the large variances among floor areas it is suggested that caution be used in applying this relationship. Department of Anthropology Washington University June, 1970 Naroll (AMER. ANT. 27:587-589, 1962) has suggested that there is a constant relationship between population size and dwelling floor area. From a sample of 18 cultures, he derived a figure of approximately 10m2 per person. The sources he used were not completely satisfactory because, in general, they were not sufficiently detailed to enable him to arrive at more than rather gross area estimates. Below are summarized some previously unpublished data from three different geographical locations. It is hoped that this addition to the published sample size with its more detailed breakdown will stimulate the collection and publication of more information on this interesting question. In each case, data were collectedby family or living group. In order to determine the variability among family units, I computed the average floor area per person for each family. I then took the distribution of these family averages and computed the standard deviation. This is used as a measure of the variability in the amount of floor area per person per family group. Case 1. I investigated two villages in Western Samoa. The village of Leipua'i on Manono Island is a small isolated village in which almost all construction is of traditional style and materials. Fasito'otai is one of the larger Samoan villages located near the town of Apia, and it has much more western influence in house design and construction. The buildings of each village were classified as dwelling units, cook houses, non-dwellings such as copra sheds, and communal buildings including churches, women's committee houses and chiefs' council houses. Only a small part of Samoan houses are used for storage; bulk food is not stored in any quantity. Eating, sleeping, or cooking is never done outside. Because of a shift of population toward the town of Apia there is a tendency for Leipua'i to be underpopulated and Fasito'otai to be overpopulated (see Fig. 1). Case 2. Watson has studied the village of Hasanabad located in Iran (EXPED. 8:9-19, 1966). It is a small tenant-farmer village with household complexes constructed of pise. Each complex usually consists of one living room, several storage rooms for dung fuel, crops, firewood and livestock, and a walled courtyard. Much household activity takes place in the courtyards or on the roofs most of the year. The total walled area of the village, including buildings, ruined buildings and courtyards, is 8584m2 or 43.3m2 per person (see Fig. 2). Case 3. Lyon collected data in a Wachipaeri village of the Hacienda Keros, Kosnipata District, Paucartambo, Peru, in the Amazon drainage. The typical family has a living house, kitchen house, and one or more animal houses. Gillin(PAPS. PMAAE 16, 1936)studied another tropical South American group, the Barama River Caribs, and his map of the Sawari settlement enabled the amount of floor areas to be determined (see Fig. 3). The large standard deviations of floor areas among family units suggest that any given household is unlikely to be a good indicator of the village average.Thus, if data are collectedby a sampling procedure, the sample will have to be large in order to accommodate this standard deviation. The present findings also indicate that computing the number of people who occupied any small group of buildings from the floor area of those buildings is a dubious procedure. In each of these cases the archaeologists collected enough specific information so that the amount of living-floor space as well as the total floor area of each village could be computed. The average total area per person (which