( Ixxi ) 



broad and often leaf-shaped. However, the Ijreadth of the hiiulwiug or the 

 dilatation of the costal margin of the hindwing is not the cause of the loss of 

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

 the 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 {Mnrumba and Lopkostethas, for instance), and such with 

 strono-ly dilated costal area of the hindwing {Stolidoptera, Ili/paedalia), which 

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

 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 occurrence of such 

 wing-characters as those together with reduced mouth-jiarts, for instance. 



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

 near the base before the hinder margin does not e.^tend beyond SM'' and stops 

 generally at SMI It is elongate and more or less pointed distally behind SM^ 

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

 sometimes subtruncate, often somewhat asymmetrical, and never elongate- 

 pointed. The non-scaled area whicb is found, for instance in Notodontidae, 

 within this patch or proximaliy of it, and which is covered with fine short 

 hairs, is not met with in Uplniigidne. 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 conspicuous— for instance in Herse 

 co/ivolviili and Pholu» labntsruc. It is situated behind M, extending occasionally 

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

 often directed obliquely costad. 



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

 hindwing 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 2| times as long as broad, with the ajjex 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 jiroximally and 

 slightly concave distally. Departures from this ty])e 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 Acherontiinae (Lapara, 

 llopliocnema, etc.) and Amhulicinae (several Poh/ptychtis, PI. I. f. 10. 11), which 

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

 a hook {L'jcoisphingia), and the hinder angle is often very obtuse, in one 

 case completely rounded {Plu/lloxipliia, PI. I. f. 4), and jiroduced backwards in 

 the rather numerous species with more deejily sinuate hinder margin (PI. I. 

 f. 5. 6. !»;. The distal margin is entire, concave, straight, or convex, bisinuate, 

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



