The most authoritative classifications of butterfly families are based upon the peculiarities of wing venation and are admirably discussed in such books as Holland's "Butterfly Book" and Comstock's "How to Know the Butterflies." Without attempting to go into the technical details of structure it will suffice here to give the list of families which compose the superfamily _Papilionoidea_: The Parnassians. _Parnassiidae._ The Swallowtails. _Papilionidae._ The Whites, Orange-tips, and Yellows. _Pieridae._ The Nymphs. _Nymphalidae._ The Satyrs or Meadow-browns. _Agapetidae._ The Heliconians. _Heliconidae._ The Milkweed Butterflies. _Lymnadidae._ The Long-beaks. _Libytheidae._ The Metal-marks. _Riodinidae._ The Gossamer-wings. _Lycaenidae._ It must not be thought that such a list necessarily indicates the degrees of development of the respective families, for this is not true. It is simply a linear arrangement adopted for convenience by leading authorities, notably Dr. Harrison G. Dyar in his standard "Catalog of American Lepidoptera." THE PARNASSIAN BUTTERFLIES FAMILY _Parnassiidae_ It is perhaps a bit unfortunate that the group of butterflies, which is commonly chosen to head the list of families, is one that is rarely seen by most collectors. The Parnassians are butterflies of the far north or of high elevations in the mountains. The four species credited to North America have been collected in Alaska and the higher elevations of the Rocky Mountains, so there is very little probability of any of them being found in the Eastern states. While, structurally, these butterflies have a close affinity with the Swallowtails, one would never suspect it from their general appearance. Their bodies are large and all of the wings well rounded, so that there is more of the suggestion of a large moth than of the Swallowtail. The coloring is also more moth-like than with most butterflies, the wings being very light colored and nearly transparent, with markings of gray and brown, arranged in dots and splashes. All our species belong to the genus Parnassius. The caterpillars show their affinity with those of the Swallowtails by having the curious scent organs or osmateria just back of the head. They feed upon such alpine plants as stonecrop and saxifrage and are well adapted by their structure and habits to the bleak surroundings of the mountain tops.