( Ixxi ) 



broiul and ol'teu leat'-sbaped. However, the lireadtU of the hiiidwiu^^ or the 

 dilatalion of the costal margin of tlie hindwing i;s not the cause of the loss of 

 the frennlnin. The absence of the frenulum and the weak power of flight are 

 tlie result of the same tendency to retrogressive development, but they are not 

 dependent on one another. There are quite a number of Sphingidae with broad 

 wings and heavy body {Marumba and Lojihostethus, for instance), and such with 

 strongly dilated costal area of tlie liindwing (^StoUdoptera, llj/paedalia), wliich 

 have preserved the frenulum. The reduction of the wing-power, the moditication 

 of the shape of the wings, and the loss of the frenulum and retinaculum occurring 

 together is to be understood in the same sense as the 0('curreuce of such 

 wing-characters as those together with reduced moutli-parte, for instance. 



The glossy patch of modified scales found on the underside of the forewing 

 near the base before the hinder margin does not extend beyond SM^ and stops 

 generally at SM'. It is elongate and more or less j)ointed distally behind SM^. 

 The scales of the j)atch are broadly rounded at the end, entire (not dentate), 

 sometimes subtruncate, ofteu somewhat asymmetrical, and never elongate- 

 pointed. The non-scaled area which is found, for instance in Notodontida,e, 

 within this jjatch or' proximally of it, and which is covered with fine short 

 hairs, is not met with in Sphingidae. In front of the patch of scales just 

 described there is another, separated from it by hair-scales. This patch is not 

 distinct in all species, but sometimes rather couspicuons — for instance in Herse 

 concohuli and Pholus labruscae. It is situated beiiind M, extending occasionally 

 into the cell, and consists of entire, more or less lanceolate scales, which are 

 ofteu directed obliquely costad. 



The glossy and sharply defined basal costal patch on the upperside of the 

 hindwiug is composed of scales similar to those of the corresponding patch 

 of the forewing. 



The generalised forewing of the Sphingidae is elongate-triangular in shape, 

 about 2h times as long as broad, with the a])ex acute, the hinder (or anal) 

 angle distinct, the outer (or distal) margin entire and shorter than the hinder 

 (or inner or abdominal) margin, and the latter slightly convex proximally and 

 slightly concave distally. Departures from this type are very numerous. 

 There occur triangular entire wings which are three times as long as broad, 

 and others (rarely) in which the distal margin is as long as or longer than 

 the hinder margin. The opposite development results in a short and broad 

 " bombycine " wing similar to that of broad-winged Notodonts or Lasiocampids, 

 with obtuse apex, a form which is found in a number of Acheront.iinae {Lapnra, 

 Hopliocnema, etc.) and Ambulicinae (several Polyptychus, PI. I. f. It). 11), which 

 have lost the typically Sphingid aspect. The apex is sometimes jiroduced into 

 a hook {Lijcospltingia), and the hinder angle is often very obtuse, in one 

 case completely rounded {Pln/lloxiplna, PI. I. f. 4), and produced backwards in 

 the rather numerous species with more deeply sinuate liinder margin (PI. I. 

 f. 5. 6. 9). The distal margin is entire, concave, straight, or convex, bisinuate, 

 dentate, scalloped, or strongly lobed, The irregular distal margin does not 



