SPHINGID^E. 



601 



With regard to the imagines, there is great variation in the 

 proboscis, the eyes, antennae, wing-shape, scaling and frenulum. 

 The variation in the proboscis is, of course, correlated with the 

 parallel modification of the pupa, and the modification of the eyes, 

 especially with regard to position, is also to be referred to the 

 specialisation of the tongue. Chapman observes that "the dominant 

 specialisation of the Sphinges is the great development of the 

 proboscis. This acts on the pupa in several directions that give 

 characters to that stage found nowhere else in the lepidoptera. 

 It has also caused various correlated changes in the imago, which 

 cannot always be directly traced to its influence, but in two cases, 

 at least, the connection is fairly obvious. One of these is the 

 immense development of the head, in many cases, really, an immense 

 development of the eyes. This does not occur in those genera in 

 which the proboscis is badly developed, or in those forms that 

 are especially day-flying. Most nocturnal moths find the antennas 

 as olfactory organs meet their requirements for finding their way 

 about, either for the $ to discover the 2 , the $ to find the 

 foodplant for oviposition, or for either to find some saccharine 

 pabulum. When the place is found, a little searching about on 

 foot is quite unobjectionable, but in Sphinx, flowers have not only to 

 be found, but the precise spot for introducing the .proboscis has to 

 be seen, and consequently it is evident that a larger eye to collect 

 more of the dim light is a necessity. The other specialisation, 

 similarly found in the well-proboscised groups, is the development of 

 the extremity of the antenna as a tactile and not as an olfactory 

 organ ; precisely why this is necessary is not perhaps fully evident, 

 but it may be useful in their rapid flight as an advance guard, 

 more probably it is of use when the proboscis is introduced into 

 the tubes of flowers in telling when the approach to the flower is 

 getting too close." We have already detailed (anted, p. 379) 

 Kellogg's notes on the scale-structure and the relation of the scales 

 to the character of the flight. Concerning this Jordan writes (in 

 litt.) : " The Sphingids of slow flight are more specialised than 

 their swift-flying near relations." Shagginess of the scaling of 

 the body and wings is not at all a sign of the insect being more 

 generalised than its smooth-scaled ally. On the contrary, the 

 shaggy body of several Macroglossids and Amorphids is a decidedly 

 new acquisition, e.g., Philampelus (recte Pholus) has a more generalised 

 scaling (see anted,, p. 379), and the rough-scaled Triptogon modesta 

 is derived from a more smooth-scaled ancestor." 



Details of the condition of the frenula of some of the species belong- 

 ing to characteristic genera are thus described by Griffiths (in litt.) : 



Pterogon 



proserpina 

 Hemaris 



fucifortnis 



Hemaris tityus 



SPINA OF 3 



Rather slender 



Very dark in colour 

 and highly polished 



Somewhat lighter in 

 colour, smaller than 

 in H. fucifortnis 



SPINUL^ OF ? . 



Compact group of 

 spinulae, 8 in num- 

 ber 



RETINACULUM OF <3 . 



Short and close 



Flat and broad ; 

 more thickly scaled 

 than in H. tityus 



Shorter than in H. 

 fucifortnis 



