,( Ixxvi ) 



jilatf i^ nut .so sliiiriily liiuited iis it iii)iK'ars to be in the figures. It doc-s not 

 bear any spines. 



Tile second type is represented liy I'l. LXIII. 1'. ."> and G. The membrane 

 connecting tlie steriiite (vii. v) with the tcrgite (vii. t) is very small; the 

 sternite is not membranaceous apically, tlie strongly chitinised jdate extending 

 right to the apex. The plate varies in form and size, occupying sometimes 

 tlie whole ventral side of the segment, the tergite being scarcely visible in a 

 ventral as))ect of the abdomen (f. 6); or it is smaller, trai)eziform, the tergite 

 encroiichiug ujiou the ventral side (f 5). The apex of the sternite is either 

 totally spinose {Sesia, Cej>hoiioiles, etc.), or at least spinose laterally {Pacl/)/gonia). 

 This tyj)e is a derivation from the first. 



The seventh sternite of the male of S/)htniii(h.ie is normal, being similar to 

 that of the sixth. The eighth sternite, however, is modified ; it is always 

 without spines, deeply sinuate as a rule, and occasionally incrassate mesially or 

 produced into a j)rocess (PI. XXII. f. 18 — !29). In the Sesiinaf and Philampelinae 

 with a stumpy abdomen (Sesia, Fachygonia, Macroglossum, etc.) it is very short. 

 The eighth tergite of the male is spinose. It varies in size and shape like the 

 seventh. It is long, and appears conical in dorsal asj/ect in Acherontiinae, for 

 instance, and short and flat in Macroglosstim, Sesia, and allies. 



The abdomen taken as a whole is mostly elongate-conical. Deviations from 

 this form, which represents the generalised type, are numerous. AVe mention 

 that the abdomen is ovate in some Uaemovvhaiiia, flat and broad in Jlypaedalia, 

 broad and stumpy in Pachi/gonia ; that it is horizontal in most species, and 

 curved upwards in many Amhuliciiuie and some Acherontiinae. 



The scaling of the posterior segments exhibits sometimes striking features. 

 The scales at the ventral apical angles are occasionally prolonged to tufts (many 

 Scsiinae and Pliilampelinae : Oxyamhulijx ; Poliana ; etc.). The long scales of 

 the seventh and eighth segments form tufts especially liable to modifications. 

 In Pacliyyonia the abdomen is triangularly truncate witli a short lateral tuft; 

 this tuft is prolonged in Himantoides, the " tail " appearing divided. The 

 expansible fan-tail found in numerous Sesiinae and Nepkelicae is generally 

 tripartite ; it occurs also in Cypa and allies, of the subfamily Amhulicinae. 

 The modification in the skeleton of the fan-tail segments consists in tiie plates 

 being short and amjily movable. There is no additional division of the 

 segments besides tlie separation into a tergal and a sternal plate. We have 

 not studied the muscular apparatus. 



The modifications of the scaling of the abdomen are very instructive. The 

 upper scales are generally elongate, more or less hair-like in. appearance, and 

 the underscales large, mnltidentate. Among the Sphingidae asemanophorae we 

 find a good number of forms which have instead of the broad underscales long 

 hair-like ones, which are often modified info lanceolate spines resembling the 

 weak spines at the apices of the segments in the respective species. Kellogg 

 drew the conclusion, from his studies of the scales of Lepidoptera, that the 

 hair-like scales represented an older type than the broad mnltidentate scales. 



