1915} == Distribution of Neuropteroid Insects 129: 
similar to our own. The same can be said of other insects; in 
Carabide Pycnochila and Omalium are such examples. Mabille 
reporting on Lepidoptera from Terra del Fuego and Cape Horn, 
remarks on the likeness of that fauna to the European and 
North American. Elwes has noted the same thing in butterflies. 
Another series of cases represent the relationship of the 
insects of the Madeira and Canary Islands to those of the Med- 
iterranean region. This has been extensively studied by Wol- 
laston and Murray for the Coleoptera, and the Neuroptera, 
though not so fully known from the islands, tell the same story. 
A series of cases, familiar to us, of discontinuous distribution, 
are those due to the advance and subsequent retreat of the 
ice-cap. The cases of butterflies and other insects and spiders 
stranded on the tops of various mountains are well known; and 
it should be noted that living with these stranded insects are 
many others that occur all over the neighboring country. The 
Holarctic insect fauna includes hundreds of cases of discontin- 
uous distribution; species the same or closely allied in North 
America and Europe. These are usually cases of divergent 
evolution, since in nearly all cases a close comparison shows 
that they differ slightly in structure, or color, or habits. 
After one is familiar with the appearance of the insects of the 
United States and begins to examine exotic forms, he naturally 
compares them with those of this country, or of Europe, whose 
fauna is well-known. 
The Neuropteroid insects that I have seen from South 
America frequently fall into our genera or are closely related 
thereto. Certain Chilian forms, and a few others like A po- 
chrysa, Dimares, etc., look foreign. When I examine the Neu- 
roptera of Japan and India the same idea appeals to me—how 
many are closely similar to our own. Here and there, as 
Perissoneura of Japan, and Palpares in India, are foreign 
forms. When I consider the Australian Neuropteroids I see 
also a number that are strikingly like those of the United States. 
Even frail and isolated genera, as example Sisyra, occur in closely 
allied species right through from United States, Europe, India, 
Japan, Insulinde, and to Australia. But with these familiar 
insects are many that are widely different from our own. 
This foreign element that I notice in South America, in 
India, in Australia is the typical African Neuropteroid fauna. 
