144 BRITISH LEPIDOPTERA. 



specialised in the front segments, being less retractile than in, say, 

 There tr a pore el lus. A form precedent to this is probably preserved by 

 Xylophanes oldenlandiae which has a spot on the 8th abdominal segment, 

 not quite obsolete, although the first two are already well-specialised. 

 No Eumorphid (as distinct from Phryxid) appears to have an eye- 

 or ring-spot on thoracic segment.* X. oldenlandiae alsohasf (according 

 to figures) less retractile front segments than other Eumorphids. 

 X. oldenlandiae thus preserves a primitive Eumorphid character, 

 though, otherwise, both it and Isoples alecto are specialised in the 

 groups they represent, larvally, as well as in the pupal and imaginal 

 instars. /. alecto, with a complete row of well-developed eye-spots, 

 is probably as far from -the primitive Eumorphid with a complete 

 row of ring-spots (as in young Fiorina japonica) as is Pergesa actens 

 with them differentiated, or Hippotion celerio with only two left ; 

 and it is perhaps misleading to take it as representing this stage 

 of the evolution. The next stage is the decline and disappearance 

 of the later spots, leaving only one or two. Weismann does not 

 say whether those with two spots originated from those with one 

 or vice versa, neither view fits in well with his general theory. We 

 have : (i) Larva with the ist spot larger than the others, passing on 

 to forms with only the ist spot, this becoming more dorsal and 

 ending dorsally. (2) In others the 2nd spot persisted as well as the 

 first, and culminated in such forms as Hippotion celerio and Theretra 

 porcellus. It does not follow that the species we now have are 

 related to one another in this larval order ; H. celerio and T. porcellus, 

 for instance, that have reached a nearly identical point, probably 

 left the main stem separately, T. porcellus not very far from /. alecto 

 (larvally), H. celerio at some distance above. Section C, as defined 

 above (p. 143), branches as follows : 



1. Same as C, but eye-spots persisting somewhat on thorax and on 8th 

 abdominal, but no retractility — Phryxids. 



2. Same as C, but eye-spots restricted to 7 first abdominal segments 

 (8th in X. oldenlandiae), and retractility of front segments appearing - 

 Eumorphids. 



a. Eye-spots nearly equal on 8 abdominal segments — X. oldenlandiae. 



b. Eye-spots nearly equal on 7 abdominal segments — /. alecto. 



c-l Eye-spots waning on abdominal segments 2-6 — D. tersa, P. acteus, 



H. clot ho, L. bisecta. 

 dj Eye-spots lost on abdominal segments 2-6 — P. vigil, my don. 



e. Eye-spots moving dorsally — hicasi. 



f. Eye-spots combined on dorsum — Elibia. 



c 2 Eye-spots waning on abdominal segments 3-6, difficult to 



distinguish, if really different, from c. 

 d 2 Eye-spots lost on abdominal segments 3-6. 



a. Earlier form — E. elpenor. 



/3. Later form — H. celerio. 



*Piepers figures a larva of Fiorina japonica, with a thoracic spot, possiblv, 

 however, an error on the part of the artist (Bacot). 



f The larva of .V. oldenlandiae is figured by Moore f Cat E. I. Mus., pi. 

 xi.) as having 8 equal spots, and almost identically by Piepers (Tijdschrift, vol. 

 xl., pi. i.). Two blown larvae, in the Brit. Mus. coll.. referred to this species, 

 have the first two spots well differentiated, ami in one there is no 8th spot, whilst, 

 in the other, the 8th spot is distinctly a spot, but not as well-developed as the 

 five in front of it (Chapman). 



