PHRYXIDI. 137 



3. Head closely set on shoulders, neither conspicuously large nor projecting; 

 forewings with a more or less well-defined fascia, very broad at inner margin, 

 with a dark discoidal blotch that nearly always lies within the fascia ; spines on 

 front tibia weak — Hyles [euphorbiae, centralasiae, dahlii, mauretanica, 

 tithymali, annei, robertsi, nicaea, costata, calverleyi). 



4. Head and tibial spines as in 3 ; forewings with an oblique conspicuous 

 line dividing the wing into a lighter and darker portion ; fascia spreading over 

 almost the whole of costal half of wing area ; discoidal spot distinct, black, 

 sometimes an indication of a dark blotch — Turneria, n.g. [hippophaes (type of 

 genus), biguttata, bienerti). 



5 Head very broad, but not very projecting ; forewings rather short, 

 less pointed than in preceding sections, almost devoid of markings ; a dark line 

 sometimes present, extending from near apex to beyond middle of inner margin and 

 much curved at nervure 2 ; spurs on front tibiae in four longitudinal rows and 

 of almost uniform size — THAUMAS (vespertilio). 



6. Antennae very long and very stout in 3 ; forewings very dark ; hind- 

 wings deep orange, with dark border reaching to margin — Hawaiina, n.g. [calida 

 (type of genus), wilsoni). 



The general characters of the Phryxids have already been 

 dealt with in our account of the Eumorphinae, and we have also 

 given (anted, p. 56) a summary of the differences between the larval 

 characters of the Eumorphids (sens, strict.) and the Phryxids. One 

 point of larval structure may, however, be here noted, viz., the 

 character of tubercle v. We have, in our description of the Sphingid 

 larva (anted, vol. iii., p. 367J, stated the opinion that the prespira- 

 cular of the larvae of Sphingids is not to be homologised with 

 the subspiracular v of the larvae of other lepidopterous super- 

 families. Bacot's recent discovery, however, that, on the 1st 

 abdominal segment of the larva of Hyles euphorbiae in its 1st 

 instar, tubercle v is not only situated in the same plane as iv, 

 but is actually conjoined to it, both the setae arising from a 

 small oval chitinous plate a short distance beneath the spiracle, 

 leaves little doubt of the correctness of what we had already 

 begun to suspect from an examination of the larvae of Sesia 

 stellatarum and Hemaris tityus in their earliest stadium, viz., that, 

 with further knowledge, the possibilites of homologising the pre- 

 spiracular of Sphingid larvae with the normal subspiracular v became 

 much easier. Tubercle v, on the 1st abdominal segment of these 

 larvae, was found to be situated on the lateral flange, and, although 

 still somewhat above iv, was distinctly below the level of the spiracle. 



We may here refer to Weismann's detailed study of the evolution 

 of the markings of the Phryxid larvae (Studies in the Theory of 

 Descent, pp. 223 et seq.). The species, with the ontogeny of which 

 he deals, are — hippophaes, zygophylli, lineata, livornica, gal Hi, vespertilio, 

 ?nauretanica, dahlii, euphorbiae and nicaea. He places (loc. cit., pp. 

 223-224) these in five groups, and states that he considers the adult 

 larvae of these five groups represent five stages in the phyletic 

 development of the tribe, but adds that, if the whole developmental 

 history be taken into account, two more stages must be added, 

 viz., (1) that in which the larva possesses no particular marking 

 (as seen in the 1st stage of development of euphorbiae and dahlii J, and 

 (2) a stage with a subdorsal line, but without any ring-spot for- 

 mations. Seven stages of phyletic development must, therefore, 

 be distinguished : 



1. Entire absence of marking in adult form — (No species now seems to 

 occur with this as the final stage of the ontogeny). 



2. A subdorsal, accompanied by a spiracular line, extending from the 



