78 INTRODUCTION. 
" The arrangement of these tribes," says Mr. "^"est- 
wood, to whose work we have been chiefly indebted 
for the above abstract ; * is admitted to be but a 
provisional sketch, of which the outhnes require to 
be filled up in future numbers of the work. It is 
consequently to be regretted that only two parts, 
comprising but a portion of the diurnal Lepidoptera, 
have hitherto been published. Dr. Horsfield en- 
deavours to complete the lepidopterous circle by 
means of Hesperia, which in its strictural characters 
and tortriciform larvae (which roll up leaves, &c.), 
exhibits a decided departure from the typical Diur- 
na, and a tendency towards some of the nocturnal 
Lepidoptera, as the Tortrices. Affinities also, of a 
more general nature, exist betw^een the Papilionidce 
and Phaltenidse. The situation of the genus Ptero- 
phorus, which, according to Reaumur and the Wei- 
ner Verzeichniss, is to be considered as intermediate 
between the diurnal and nocturnal Lepidoptera, he 
does not attempt to deteniiine. "With the excep- 
tion, therefore, of the diurnal species, but little pro- 
gress is here made in the classification of the order. 
A plan is indeed indicated for its natural arrange- 
ment; but it appears to me that the nocturnal 
groups will be found, when more satisfactorily 
investigated, by no means to correspond to these 
views." 
Numerous and various as are the forms and as- 
pects of the caterpillars of the lepidopterous tribes, 
!Mr. Swainson thinks that they may nearly all be re- 
ferred to five principal types. These he names : — 
* Modem Classification of Insects, vol. ii. p. 328. 
