212 A Classification of Lepidopterous Larvae. 



Harrisina americana Harris. 



Head retracted and concealed beneath the prothoracic segment. 

 Body flattened, sides nearly perpendicular with a distinct substig- 

 matal ridge. Four rows of low, flattened areas, representing warts, 

 granular, and bearing numerous, radiating, short, fine bristles, and a 

 few longer whitish hairs from the extremities of the body. Tuber- 

 cles arranged (1) subdorsal, (2) lateral, (3) substigmatal, and (4) 

 obscure, above the base of the leg. 



Family Megalopygidae. 



The arrangement of the tubercles is the same as in the Pyro- 

 morphidag. The two additional pairs of abdominal feet, unique in 

 this family, have long been known. They were cai*efully described 

 by J. C. Sepp in 1830' in the case of Megalopjyge xanthopasa and 

 M. lanata, and have recently been noticed by several authors. In 

 the case of our native species, 31. crispata, Dr. Packard, in a recent 

 paper^ gives a general summary of these structures with some ex- 

 cellent figures. He concludes thus: As to Megalopyge " with its 

 rudimentary abdominal legs of the 2d and Uh segments of the hind 

 body, we feel warranted, in the present state of the subject, in con- 

 cluding that they may represent a persi-stent condition of two pair 

 of these deciduous abdominal legs" (which appear in embryonic 

 development). From this assumption he very naturally concludes 

 that Megalopyge " in respect to its abdominal legs, even if we do 

 not take into account other characters, is a survivor of an ancient 

 and very generalized type, and represents, as no other known cater- 

 pillar, the polypodous ancestor of all Lepidoptera." Of course this 

 conclusion is entirely opposed to my view of the relationship of the 

 Megalopygidae, and I cannot accept Dr. Packard's assumption. I 

 regard the development of these additional abdominal feet as secon- 

 dary. This family distinctly leads up to the Eucleidge, and this 

 .structure shows us how they probably derived their peculiar mode 

 of progression ; for an extension of the modification of the ventral 

 surface which has here begun, would give us the slug-like structure 

 of the EucleidiB, the most remarkable of all Lepidopterous larvae.'' 



1 Surinaamsclie Vliiiders, vol. I, expl. to pi. 14. 



2 Proceedings Arner. Pliilos. .Soc, vol. XXXII, pp. 275-292. 



^ Dr. Packard has stated in several publications that the Eucleid;e (= Lima- 

 codidie = Cochliopodidfe) have' no thoracic feet. This is an error ; the feet 

 are distinctly present, though small. 



