19131 Variation in the Genus Lucilia. 253 



Lucilia angustifrons. Town. 



The type specimen is a cf from England and the single 

 co-type is a 9 from Kaslo, B. C, which "seems to be this 

 form " (Townsend, Taxonomy of Muscoidean Flies, p. 120). 

 An examination of the type shows that a third and anterior 

 pair of postacrostichal bristles is present; at the same time 

 both these bristles are weaker than those situated posterior to 

 them in the same rows and moreover the bristle on one side 

 is decidedly less strong than that on the other side (the one on 

 left side is weaker). This is the only character that separates 

 the fly from typical L. caesar and as in this very character 

 there is an irregularity it seems highly probable that the pair 

 of bristles is nothing but a sport in which case the form must 

 be referred to L. caesar Linn. 



As to the single co-type, the 9 from Kaslo, this fly has 

 two postacrostichal bristles on one side and three on the other 

 with the anterior one weak; the fly is unquestionably L. caesar 

 Linn. 



Lucilia giraulti. Town. 



One cf from Paris, Texas, no cotypes. In the original 

 description of this species (Townsend, Taxonomy of MuvS- 

 coidean Flies, p. 121) there is only one character mentioned 

 that would separate the form from L. sericata Meig. which is 

 that "a second pair of ocellar bristles is present." Even 

 were this so the character would be insufficient in itself as the 

 study of variation for L. sericata, brought out the fact that 

 in this species there is occasionally developed a second pair 

 of ocellar bristles. An examination of the specimen itself 

 however shows that the bristles in question are not developed. 

 The fly is therefore L. sericata Meig. 



Another character used in the description of this species 

 is the position of the postacrostichal bristles relative to the 

 dorsocentrals. The study in variation brought out the fact 

 that this character has no determinative value. The above 

 specimen is badly mutilated. 



Lucilia barberi. Tow^n. 



A discussion of this supposed species is hardly necessary. 

 All the characters employed to separate the form are met with 



