ENTOMOLOGICAL NEWS. IO9 



The occasional absence of the third anterior dorso-central or, 

 to put it in other words, its reduction to such a size as to make 

 it indistinguishable from the other hairs of that region, would be 

 expected by one who had studied the eleven specimens of the 

 first group wherein there was a deficiency in the size of this mac- 

 rochseta. In regard to the absence of one or both of the second 

 posterior achrosticals I would say that throughout the Muscidae 

 (sens, strict.) I have found that the number of pairs of achrostical 

 macrochaetae is usually a specific character, although sometimes 

 variable, and that in Cynomyia mortuomm (as far as my limited 

 amount of material enables me to determine) there is but one pair. 



Presence of macrochaetae normally absent was observed in 

 twenty-three cases (9.4 per cent), two of which showed also ab- 

 sence of macrochaetae normally present and will be separately 

 considered. The abnormalities observed in this group were : 



A third right anterior achrostical present; one male and one 



female. 



A third left anterior achrostical present ; one female. 

 A third right posterior achrostical present; two males and one 



female. 



A third left posterior achrostical present; one female. 

 A third pair of posterior achrostical present; one female. 

 A small pair of anterior intra-alar, right one half the size of 



the left; three females. 

 A third left posterior intra-alar, about a quarter as large as the 



second; two females. 



A third pair of posterior intra-alars; two males and two females. 

 A second left marginal scutellar ; one male and one female. 

 A second left discal scutellar; two females. 



The presence of a third anterior achrostical on one or both 

 sides I have also observed in the typical Calliphorae, and it is 

 present in both my female specimens of Cynomyia elongata. The 

 third pair of posterior achrosticals occurs in my females of Cyn. 

 elongata, and is always present in the typical Calliphorae. The 

 anterior intra-alar is present in all my specimens of Cyn. elongata 

 and in all the Calliphorae and nearly related genera. The third 

 posterior intra alar is normal in an undescribed species of Calli- 

 phora, of which I have numerous specimens, and is occasionally 



