A stock of Drosophila waelanogaster, now being investigated at the University of IJtah, shows conspicuous growths on the various parts of the head other than the mouth parts. The stock was obtained in 1946 from Dr. %7ilson Stone of the University of Texas. Dr. A. B. Griffen, now at the University of Missouri, informs the writer that the trait first appeared in the spring of 1945 in a wild stock under his care at the Gniversity of Texas. The original collection was made at Acahuizotla, Mexico, in 1941.
When first obtained the penctrance of the trait was about 6470, but after two years of selection it has increased to 76% at 22ยฐC. Dr. E. J. Gardner and Mr. Charles Woolf (in press), of this laboratory, have been studying the inheritance of the trait. They have established that the expressions here described represent those of a single trait and present an hypothesis on its inheritance.
Temperature experiments, by Mr. Woolf, are now in progress. These show an influence of temperature upon penetrance and viability with differences in the two sexes, but no conclusions may yet be drawn.
Rice and distribution of the growths. The growths vary in size and form a series from very small, inconspicuous ones
The cstablishment of The Genetics Research Laboratory in which this investigation was carried out has been aided by grants from the University of Utah Research Committee. This support is gratefully acknowledged.