. c 409994 [he beetle acquires a golden ap.!rtce (which is absent in strains ~re not au) that is evident even c presence of body-color genes such e[y (3). I order to assess the effect of the :cne. counts of setae were carried .~n two parts of the body of ten M derived from the au and ten I the normal Texas stock, namely, ;entral portion of each visible abnal sternite and the distal portion .Imputated memand mounted .ous wings which is free of veins. ‘w sternites, the setae were counted a single area 0.01 mm: in the NC of the sternite, with the aid of (ic?e in a 1SX ocular in comhina\\,i[h a 10X objective. In the mem!Y.IS wings the setae within five . of each wing selected at random, i 0.02 mm~. were recorded with a ocular and 44x objective. : the sternites of the normal beetles :]Sean setal number in a sample of >pecimens varied from 9.4 ti 0.2 ‘~.7 & t).4 setae. In au these values wd from 23.7 = 2.1 to 30.6 & 1.4 .’. or approximately two to three . as many as in the normal beetles. .he membrwtous wings the mean :ber of setae in the sample of 50 \urements in each strain was I 0.84 ~~ for the normal and 11.10 & 1.66 {he mutant. The difference in the I means is not statistically significant . .4). ‘he micrographs obtained with the nning electron microscope are shown eig. 1. At the top, on the lefi is w part of the head and the pro~tx of the normal beetle, and on right that of the au mtitant. Clearly, number of pits and associated brisicre greatly increased in these two m of the body. The cervical bristles !he anterior” margin of the prorux are also greatly increased in nber. 1he micrographs of the abdominal mites (in the middle of Fig. 1) show what extent the number of pits and .tles is increased in the mutant. ~lnal. on the bottom of the figure are two ~rographs which contrast the commd eye of the normal and the mu! In the normal beetle (left) there ordy single bristles between the omlidia, while in the mutant (right) interornmatidial bristles are often :ibled. rhe cytogenetic basis of most mu[s other than those from Drosophila ii~ I[!LY 1967 Refesenee* tnelanogaster is not known. In Drosophila the sex-linked dominant Hairy- 1. T. L. Hayes, wing (Hw) increases the number of hairs present in the normal wing. For exarnpl% in Hw/ + females the number is increased by about 17 hairs, in Hw/Hw by about 21 and, combined with a duplication (Dp), in Hw/ Hwl Dp by about 33 extra hairs. The increase in hair number was less marked in males. Cytological examination and genetic data revealed that the increase in hair number resulted from a duplication. The duplication essentially doubled the number of extra hairs on the wing (4). The autosomal recessive “hairy,” which increases the numbers of hairs on the wings and other parts of the body, interacted with Hw to increase the number of hairs on the wings even further (5). In Triboliurn the cytogenetic basis of the aureate mutation has not been investigated because, even with the most powerful compound microscope, the chromosomes are too small to detect chromosoma[ aberrations such as duplications or deletions. As techniques are developed in conjunction with the scanning electron microscope, it should be possible to examine cytological material and determine whether chromosomal aberrations (such as duplications in Drosophila) are responsible for the modMcation of the phenotype of Triboliurn. Be that as it may, our data indicate that the aureate mutation in its effect appears to be unique so far, not only but for the for the genus Tribolium order Coleoptera (6). Furthermore, because the scanning electron microscope gives micrographs of high resolving power even at high magnifications, it has been possible to obtain a detailed record of the phenotype of normal and mutant to a degree not previously attainable. A. SOKOLOFF Department of Genetics, University California, Berkeley, and Natural Sciences Division, California State College, San Bernardino of T. L. HAYES Law’rence Radiation Laboratory, University of California, Berkeley R. F. W. PEASE Electronics Research Laboratory, University of California, Berkeley M. ACKERMANN Department of Genetics, Univer.rity of California, Berkeley Donald, Lab. and Notes R. F. W. Pease, L. W. Mc-