246 Annals Entomological Society of America [Vol. VI, 



RESUME OF L. SYL VARUM. 



There were in all cases 3 strong pairs of dorsocentral bristles, 

 but in 33% of the flies resulting from one egg cluster there was 

 a trace of a fourth anterior pair; sometimes this trace exhibited 

 itself as a slightly exaggerated hair on one side only and some- 

 times it resolved itself into a distinct but weak pair of anterior 

 dorsocentral bristles. There were three pairs of strong 

 postacrostichal bristles in all cases. 



As regards humeral bristles there were in most cases four 

 on each side. The majority of variations ran to an abortion of 

 either one bristle on one side only, or of a bristle on both sides. 

 This bristle was always the anterior bristle and, as in L. sericata, 

 the loss of it carried with it a weakening of the anterior one. 

 There was in one case a variation in the other direction, namely, 

 the development of an extra bristle, quite strong, on one side 

 only. 



Sternopleural bristles were represented by three typical 

 pairs, but, as in L. sericata, there was variation, notwithstanding 

 the fact that the character has an undoubted generic value. 

 This variation appeared in 4 specimens and ran in each case 

 to an additional anterior pair, represented either by a bristle 

 on one side only or by a bristle on each side; these bristles 

 were sometimes weak and sometimes strong. In all cases 

 as in L. sericata, only the anterior bristles were subject to 

 modification. 



Coming to ocellar bristles it was found that, as in L. sericata, 

 these afforded secondary sexual characters. The four males 

 had only one strong pair of ocellar bristles. These were proc- 

 linate and inserted within the ocellar triangle. 



The females had one strong pair inserted within the ocellar 

 triangle and one very weak pair inserted outside the triangle 

 and immediately posterior to it. This weak pair was made 

 up of somewhat exaggerated hairs but the term bristle is 

 perhaps applicable because they stood out from the surrounding 

 hairs (of which there were several pairs). There were in the 

 specimens of this species as in the specimens of L. caesar a 

 few hairs within the ocellar triangle. There was variation 

 from the typical condition of one strong pair and one weak in 

 two directions, namely, reduction of the posterior pair and the 

 addition of another posterior pair of these weak bristles or 

 strong hairs. 



