BUTTERFLY SOUNDS 97 



result (none is perceptible to human ears) in the 

 structure of the lowest vein of the front wing. He 

 examined Callophrys rubi, and states that the vein 

 is bare and " crossed at uniform distances by pro- 

 nounced striae, which indicate internal diaphragms 

 and constrict into a series of bead-like formations." 

 This statement has been accepted without exami- 

 nation by some entomologists, yet it is not true. 

 The vein is never bare of scales except when they 

 have been rubbed off, and the markings seen by 

 Swinton are either the threads of the inclosed 

 tracheae or the lines of pockets for the attachment 

 of the abraded scales. But what one does find (in 

 all Lycaeninae, apparently, certainly in all of our 

 species) is that in the lowest interspace of the 

 front wing, next the inner margin, there is a patch 

 of scales of a different character and setting from 

 any other scales on the under surface. The patch 

 does not reach the base of the wing, nor extend 

 much if any beyond the basal third of the wing, 

 but occupies the whole width of the interspace, 

 and is found in male and female alike, just as the 

 wing movement is shared by both sexes ; the scales 

 are slenderer than those about them, subfusiform 

 and bluntly pointed, and very often erect or nearly 

 erect ; but they have one other important quality 



