. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DROSOPHILA MELANOGASTER 89 representing square mm. at a given magnification have been pre- pared by projecting through an Abbe camera lucida mm. from an object micrometer placed on the microscope stage. A Spencer microscope was used with objective 4 mm. and ocular [ 10. The hairs have been projected by means of the camera lucida and drawn with a sharp pencil. Only hairs whose bases happened to fall inside the square have been counted (Fig. 2). A/or/na/Sy fed a £o/d fe/nperafare \ OOO_ T /<OO_. FIG. 2. This figure
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. DROSOPHILA MELANOGASTER 89 representing square mm. at a given magnification have been pre- pared by projecting through an Abbe camera lucida mm. from an object micrometer placed on the microscope stage. A Spencer microscope was used with objective 4 mm. and ocular [ 10. The hairs have been projected by means of the camera lucida and drawn with a sharp pencil. Only hairs whose bases happened to fall inside the square have been counted (Fig. 2). A/or/na/Sy fed a £o/d fe/nperafare \ OOO_ T /<OO_. FIG. 2. This figure represents the bristles on the surface of in the lower surface of the wings of underfed, normally fed, and cold temperature fe- males. The bristles which have a line across their middle have been counted, those without lines had their basis outside the limits of the and have not been counted. We did not consider it wise to count the hairs exactly at a certain point (in so many parts of a millimeter from a certain vein) as has been done by Dobzhansky. There are two reasons for not doing so. First of all the distribution of hair on that part of the wing is more or less uniform. On the other hand, the wings of underfed and normal are so different in size that a distance expressed in absolute measurement would show morphologically quite different regions. Fifty specimens of each set of underfed, normal fed and 18° flies were studied in regard to the density of the hairs. Dr. Th. Dobzhansky succeeded in finding that on the wings each hair corresponds to a separate cell. This can be seen on specimens of flies just emerged from the pupae. The wings look opaque and the cells can be distinctly seen. It is very likely that the tiny hair covering the thorax of Drosophila corresponds also to hypodennis cells, and their density may also be used as a method of studying the size of the hypodermal cells. III. It is desirable at this stage to digress briefly to consider a ma
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
