206 DR. ROYSTON-PIGOTT ON VILLI ON 



Occasionally they are seen to lie flat upon the basic membrane, 

 and to be connected by cross ramifications, interlacing in an extra- 

 ordinary manner. At other times the bases of the villi are ciliated, 

 forming, reticulations, resembling ancient hieroglyphics or archaic 

 writing. Their thickness varies from ^-5-5-^ to tWooo °^ an mcn > 

 and their length is sometimes prodigious. 



The villi principally observed at present take the following 

 forms : — 



I. Beaded Villi. 



II. Embossed Villi. 



III. Pillar Villi. 



IV. Ciliated Villi. 



V. Connected Villi. 



VI. Banana or Bunched Villi. 



VII. Spinous Villi. 



VIII. Tall Villi. 



Out of about 400 preparations (dry mounts) of scales obtained 

 from all parts of the world, I propose to select a few which with good 

 object glasses give some startling results. I should here premise 

 that when the heads of the villi make contact with the cover 

 glass they always produce black circular discs more or less minute. 



I. Beaded Villi. Papilio erectheus ; male ; Australia. Hind 

 wing of butterfly. Powell's l-12th oil N.A. 1*43. Innumerable 

 black contact heads of villi on dark red scales, which generally show 

 brilliant test beads, glittering with extraordinary beauty and pre- 

 cision of form. Between open ribs are scattered irregularly re- 

 markable isolated beads, varying much in size. With very fine 

 object glasses these beads exhibit jet black or blue black circular 

 margins and bright focal discs. 



II. Embossed Villi. Zygoma lonicera. Some of the dark 

 scales of this moth display amazingly large embossed villi of 

 irregular shape. The long scales are the most beautifully marked, 

 and the villi are in places much prolonged. The scarlet and steel 

 grey scales show unusual thickness, and when the ribs lie upwards 

 the spots or villi appear a long way below them, attached to the 

 other or unribbed membrane. But even the little short grey scales 

 reveal very long filamentous villi developing into villi broad and 

 and black. Zygoma lavendulce exhibits also most extraordinary 

 irregular villi on dark scales. 



III. For Pillar Villi examine scales of Papilio philenor. The 



