ZOOLOGY AND BOTANY, MICROSCOPY, ET(J. 65 



macrochffitae ; the ch^totaxy, or arraDgement of bristles ; and the genital 

 apparatus. The taxonomic v^alue of the different characters is discussed, 

 and the genera mentioned are contrasted with Sarrophaga, the third genus 

 in the family. 



New Genus of Blepharocerid Flies.*— F, W. Edwards establishes 

 the new genus Elporia, to receive what he previously described as 

 KeUoguina banmnli. The new genus differs from Kelloggina in having 

 divided (dichoptic) eyes, and from Paltostoma in the longer male palpi, 

 the absence of mandibles in the females as well as the males, the shorter 

 proboscis, the divided eyes, tlie structure of the last tarsal joint, and 

 details of the spines, respiratory iilaments, and anal papilla of the larva;. 

 The author describes Elporia capensis sp. n., which differs markedly from 

 E. harnanU in all its stages. The respiratory tufts and the larval spines 

 seem to be of considerable systematic importance. 



Inheritance of Bristles in Drosophila f— Edwin Carleton MacDowell 

 has studied the inheritance of extra bristles on the thorax of Drosophila 

 ampelophila. There are normally four bristles forming a rectangle on 

 the dorsal surface of the thorax. The extra ones occur in the two 

 longitudinal rows of the normal bristles, or just medially or laterally to 

 these rows. From a pair of Avild flies a race was established which had 

 regularly more than the normal four. By selecting high-grade parents 

 and inbreeding brother to sister the number of bristles was gradually 

 inci-eased (up to nine extras) for six generations. From the seventh to 

 the eleventh generations fluctuations were found showing no further 

 increase. The maintenance of the high grades of extra l)ristles does not 

 depend upon selection, for low-grade parents from mass cultures started 

 from the fifth and sixth generations that have run eight months give, 

 when raised as single pairs, as high-grade offspring as inbred and selected 

 parents mated at the same time. 



A Mendelian factor is involved in the inheritance of extra bristles, 

 and as normal dominates extra, this may be regarded as a dominant 

 factor that restricts the number of bristles to four. This factor is not 

 sex-linked, although the males are apt to have fewer bristles. 



The extracted extra-bristled flies have a lower distribution than that 

 of the inbred flies of the corresponding generation, although the high 

 extremes of the inbred race are also found among the extracted extras. 

 There is a greater difference between the inbred and extracted distribu- 

 tions when the cross is made af t*er eight selections than when made after 

 only one selection. Environment influences the number of extra bristles, 

 and the amount of food is very important. 



The author adopts the hypothesis that the extra bristles are due to 

 the absence of one main restricting factor, and their number is also 

 influenced by accessory restricting factors, which, in the absence of the 

 main one, produce flies with reduced numbers of extra bristles. 



* Ann. Nat. Hist., xvi. (1915) pp. 203-15 (22 figs.). 

 + Journ. Exper. Zool., xix. (1915) pp. 61-98 (6 figs".). 



Feh. 16th, 1916 F 



