ULLER in 1927 stated that the “partial sterility” of X-rayed males M of Drosophila wasdue,at least to an appreciable extent, to dominant lethal changes induced in the sperm. It was impossible, however, to determine whether the eggs were actually “fertilized.” In Drosophila the result would be the same; the eggs would fail to develop, whether dominant lethals were induced or the sperm were inact...

HE technique for classifying oocytes of irradiated females of the parasitic Twasp, Habrobracon, into those exposed in first meiotic prophase (prophase I ) and those exposed in first meiotic metaphase (metaphase I) was described by the author in 1945 (1945a). Methods for greater accuracy in estimating lethal rates were described by ATWOOD, VON BORSTEL and WHITING 1956. The striking difference in...

The two autonomously manifesting mutations, eyeless (el) and white eyes (wh), of Habrobracon juglandis were compared phenotypically with the wild-type. Eyeless reduces the compound eyes in size. The penetrance is 100%, while expressivity ranges from point-shaped ommochrome crumbs over individual facets to a small eye with abundant facets. There is no correlation between the sizes of left and ri...

Cells of the wasp, Habrobracon juglandis, were studied by electron microscopy with the view to comparing ultrastructural changes, especially those found in mitochondria, that occur during the first two-thirds of the 29 h embryonic period. In 1- to 2-h embryos (the earliest studied) mitochondria are distributed principally in the periplasm and typically are arranged in clumps with their long axe...