( xlvii ) 



terms. We divide the SphiiigiJae into the i'ollowing eight classitiiuitory 

 categories : — 



I. Individual variet}'. 

 II. Generatory variety = seasonal variety. 



III. Geographical variety = subs]>ecies. 



IV. Species. 

 V. Genus. 



VI. Tribe. 

 VII. Subfamily. 

 VIII. Family. 



Before we proceed to state some of the general results of our study of 

 tlie Sphinqidae, we give a summary of tlie raor[)hology of these insects, which 

 will enable the reader to more fully comiirehend some of the conclusions 

 bearing on phylogeny and distribution. 



MOKFHOI.OGY OF SFHINGISAE. 



The dorsal skeleton of the head (PI. LXII. f. 6) is divided by two 

 transverse sutures into clypeus {cl), epicrauium {ecr), and occiput {occ). The 

 last is always a narrow transverse plate more or less distinctly placed at an 

 angle to the convex epicrauium ; it is as a matter of course longer transversely 

 in those species in which the eyes have a more oblique position than in those 

 which have less obliquely placed eyes. Comjiare PI. LXI. f. (i and PI. LXII. 

 f. G. Its anterior edge is generally faintly incrassate in tlie middle. The 

 ej)icranium forms laterally the sockets for the antennae, which stand nearer 

 the eye in some Hawk Moths than in others ; the suture between epicrauium 

 and clypeus is just in front of the antennae, ending in the antennal grooves. 

 The clypeus is the largest plate of the three; it is more or less strongly 

 convex, especially mesially. It bears at the anterior margin the labrum 

 {Ir, PI. LXI. f. 6. 8. 9. 10. 11, also PI. LXII.). The two are almost merged 

 into one, the suture being mostly not distinct. The labrum is in most instances 

 raised to a large, transverse, cariniform tubercle, which is generally vertical in 

 front. It projects sometimes frontad over the base of the tongue, concealing 

 the mesial part of the epistome {ej>), and is occasionally very small (PI. LXII. 

 f. 3). The epistome is a transverse plate of variable dimensions situated in 

 front of the labrum, with which it is so completely fused that it is not easy 

 to say where tlie one begins and the other ends. It is especially hirge in 

 a number of Ambnlicinae with otherwise reduced mouth-parts {rp, PI. LXI. 

 f. 10. 11 ; PI. LXIL f. 4. 5). 



This epistome covers the base of the tongue. When normal, it has a thin 

 mesial lobe and a large process at each side. The mesial lobe varies in size and 

 somewhat in shape, and is rarely absent (PI. LXI. f. 10 ; PI. LXII. f. 1), this 

 occurring when also the other mouth-jiarts exhibit a high degree of reduction. 



