3 
Phalaenae, Moths. 
While the butterflies consist of only a few families, all closely related to one another with the exception 
of the Hesperidae, the very heterogeneous moths are composed of a long series of often very differently organ¬ 
ised families, as has already been mentioned in the introduction to vol. 2. 
The numbers of the families in the present volume do not agree with those of the corresponding vol¬ 
umes dealing with the other faunistic regions because the families are not all distributed over the entire globe. 
Very little of a general nature can be said about the American Heterocera. There is a certain similar¬ 
ity to those of the Old World inasmuch as in the Eastern Hemisphere the duller coloured insects, which are 
adapted to tree-trunks and rocks, belong to the North, and the more brightly coloured diurnal ones to the 
South, this being also the case in America, where there is a distinct difference between the wintry North 
(Nearctic Region) and the hot South (Neotropical Region), the line of demarcation drawn between the two 
faunistic parts of the Western Continent in other works being quite justified. It is only for technical reasons 
that we have decided to deal with the whole of America in one single section and not in two separate ones. 
Only about 4000 forms of Macrolepidoptera are found in the countries north of Mexico, inclusive of the Co.s- 
siclcie, Thyrididae and Sesiidae hitherto counted as Macros (to which exception might be taken from a scientific 
point of view); while many times this number occurs in the scarcely larger Neotropical Region. 
As the butterflies and moths of America live under the same physiographical and especially climatic 
conditions a similar effect must be expected in both divisions of Lepidoptera. 
The brilliant colouring and metallic reflexions found among the Castniidae, Syntomidae, Pericopiinae , 
Saturniidae, Sphingidae and many Geometridae of Southern America are produced by the dazzling sunshine of 
the South in connexion with the dampness of the atmosphere; while northern forms are characterized by 
softer, duller and less conspicuous colouring. The schemes of markings also bear the stamp already described 
several times in the section devoted to butterflies, viz. in the North we find complicated patterns poor in contrast 
resembling bark and rocks, in the South brightly coloured decorative bands and spots on a deep black ground. 
Very different methods must be adopted for collecting moths in the North and South of America. Col¬ 
lecting at the lamp is in the South sometimes quite successful, but may also yield nothing for months at a time. 
Baiting, on the other hand, is more successful in the North than in the South, where, if one has recourse to 
it at all, much larger quantities of the bait (large heaps of rotting fruit, puddles of strong-scented liquid, etc.) 
must be employed. Very little of a general nature can be said, and it is necessary for the collector to acquire 
special experience almost in every different district and in every family. 
I. Section: Bombyces. 
As regards the extent and subdivision of this group, we refer the reader to what is said in 
Vol. 2, page 3. The number of forms amounts to several thousands, not one-third of which -— altogether not 
1000 species —- belong to America north of Mexico. In the extreme North the American fauna contains few and 
inconspicuous forms, some of which are identical or congeneric with Arctic species of the Old World. In the 
most northern latitudes the Gynaephora (rossi and groenlandica) head the list, and a few species in Labrador 
are so similar to those of the Arctic district of the Old World that many authors feel justified in including this 
part of America in the Palearctic fauna, their reasons for so doing being quite sound. In Canada and the 
United States also many forms occur parallel to those of the same latitude in the Eastern Hemisphere, but the 
number of species common to both Hemispheres diminishes more and more, whereas the congeneric species are 
still of frequent occurrence, though not to such an extent as among the Rhopalocera. 
South of the Mexican deserts the character of the fauna alters so completely that only very few cosmo¬ 
politan forms remind one of the Eastern fauna, just as among the butterflies only the Painted Lady and the 
Camberwell Beauty extend south beyond the Neotropical boundary. The height of abundance is reached in the 
