THE SPHINGO-MICROPTERYGTDES. 127 



freer circulation, and more equable temperature, this combination of 

 favourable circumstances causing them to eat more. He says : " The 

 fat, overgrown slugworms (Eucleids) may be compared with the over- 

 fed, high-bred pig, which eats voraciously, has little need of rooting, 

 and takes but little exercise. Where, as among cave animals, there 

 is a deficiency of food, we have a constant tendency to slimness, to 

 an attenuation of the body. This is seen in the blind cave Arthro- 

 pods compared with their allies which live under normal 



Conditions." 



The generalised superfamilies of the stirps present us with a free, 

 or with an incomplete, pupa, i.e., Pupa-libera and Pupa-incompleta 

 of the earlier authors. Pupae of the former kind occur in the Microp- 

 terygids (?), Nepticulids, Eucleids and Megalopygids, of the latter, 

 in the Anthrocerids, Psychids and Pterophorids, whilst the remaining 

 superfamilies have obtect pupae, /.^, the Pupa-obtecta of the early authors. 

 These two divisions, therefore, fall into Chapman's two sections, 

 Incomplete and Obtecte respectively. The free pupa of the Microptery- 

 gids (?), Nepticulids, and Eucleids, probably represents one of the most 

 generalised of all existing forms of lepidopterous pupa?, having all 

 the abdominal incisions movable, and the appendages free, i.e., not 

 soldered. Those of the Anthrocerids, Psychids and Pterophorids, are 

 but little more specialised. They have traces of the "eye-collar" 

 (maxillary palpi), a character almost entirely confined to the most 

 primitive pupal forms, and well-developed in the Nepticulids and 

 Eucleids. In the Anthrocerid pupa the free abdominal segments are 

 3, 4, 5, 6 and 7 in the male, and 3, 4, 5 and 6 in the female. The 

 Psychid and Pterophorid pupae are more specialised, having only 4, 5, 

 6 and 7 free in the male, and 4, 5 and 6 in the female. That of 

 the latter is remarkable also from the fact that it has a well-developed 

 cremaster. It has not, however, a silken central body girth. 



When obtect rank is reached there are few structural characters 

 that can be used for differentiation, owing to their uniformity, but it 

 may be noticed that the Lasiocampid pupa has the dorsal head-piece, 

 a character that suggests this as the lowest of the obtect superfamilies of 

 the stirps. The delicate pupal integument is probably another vestigial 

 character. Strangely the obtect pupa of the Endromids has retained 

 the remarkable Micro character of pupal locomotion. This is a 

 peculiar habit exhibited by the pupae of the more generalised Eucleids, 

 Anthrocerids, etc., by means of which they leave (more or less com- 

 pletely) the cocoon before the emergence of the imago. The same 

 phenomenon is exhibited by certain Sphingid (Choerocawpa) pupae, 

 whilst that of Macrothylacia mbi travels to and fro in its long cocoon 

 in order to take advantage of the heat of the sun. 



As might be expected, the diverse habits of the imagines of the 

 various species comprised in the superfamilies of which this stirps is 

 composed, have resulted in a marvellous difference in the imaginal 

 forms, some of which are extremely specialised, each in its own par- 

 ticular direction. Without going into detail, we have the heavy-bodied 

 Eucleids, Lasiocampids, Endromids and Saturniids, the males with 

 strongly pectinated antennae, dashing about with exceeding swiftness 

 in the hottest sunshine, the females lethargic by clay, and flying heavily 

 by night when ovipositing. There are the microscopic sun-loving 

 Nepticulids, and the dusk-loving Pterophorids. The Anthrocerids 



