BY R. J. TILLYARD. 307 



But it is necessary to move the foreiving sharply forward, if one 

 desires to secure the coupling of the two wings in the male. In 

 doing this, the stationary frenulum is caught up by the moving 

 hasp-like retinaculum; and the grip, once effected, is not easily 

 lost. 



AVe may sunnnarise these results briefly as follows: — 

 Fetnale. — Unspecialisedyr('>i///?/?/iof from two to nine separate 

 bnstles set closely together. Unspecialised retinacubim of stiff 

 hairs or scales directed anteriorly, and developed from tlie under- 

 side of the cubitus of the forewing. 



Male. — Specialised frciiuluiit of a single, large, composite 

 bristle, formed by fusion of the original series of separate bristles. 

 Specialised retinacidnrn in the form of a chitinous hasp, directed 

 posteriorly, and developed from the underside of the radius. 



B. Amplexiform Types. 



The groups which haxe lost tlie frenulum and adopted the 

 amplexAfomt type of wing-coupling (in which connection is main- 

 tained simply by overlapping of the anal area of the forewing 

 upon the well developed costal area of the hind, including the 

 enlarged humeral lobe) may be arranged in three super-families; 

 viz., the Saturniina, the Lasiocampina, and the Papilionina or 

 Rhopalocera. These three do not appear to be very closely 

 related. 



The Saturniina comprise the large and highly specialised group 

 of the Atlas Moths or Emperors. These possess neither frenulum 

 nor proboscis, and have a highly specialised venation. Meyrick 

 places them as the last of his series Notodontina ; but this 

 arrangement does not seem to be generally accepted by other 

 Lepidopterists. 



The Lasiocampina form a natural group, if the E upterotidoi 

 and DrepauidcB be included in them. In the former family, a 

 frenulum is present; in the latter, most of the genera show a 

 small or reduced frenulum. In the other two families, the 

 Bndromidie and Lasiocampidce, the frenulum is absent. These 

 last show a very high specialisation of the amplexiform arrange- 

 ;enera. For instance, in Lasiocampja, the 



