22 
MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
which are rather long and slender, acute, tipped with brown, with the anal proleg rather large 
Legs rather long and slender; tarsi ending in a single claw. Color whitish; head and prothoracic 
segment slightly tinged with honey-yellow. Length, 5 mm . Three specimens, apparently not fully 
grown, as they were small in comparison with the beetle. They were found on boards forming the 
steps in the entrance of the cave, in perpetual darkness however, and had evidently been artifi¬ 
cially introduced. 
This genus belongs to an interesting family, as the larv;e of Metoecus, Rhipiphorus, Symbius, 
and Horia, live in wasps’ nests, and Rhipidius is a parasite on Blatta germanioa. The young of 
Mordella and Anaspis, however, burrow in the stems of herbaceous plants, while the larvae of Mor 
della, fasciata Fabr. in Europe live in the “dead wood of the poplar.” 
From Alabaster Cave, California, situated in El Dorado County, Dr. Horn has described an eye¬ 
less beetle, Anillus explanatus. (Trans. Amer. Ent. Soc., NY, 26,1888.) The name of the collector 
is not given, but on July 6, 1886, Mr. E. A. Schwarz wrote me as follows regarding an alleged 
Anophthalmus from a cave in California :* 
I have examined the Californian specimen collected hy Mr. Koebele near Sacramento and find that it is no Anoph. 
thalmns at all, but a large Anillus, which is possibly different from A. debilis Lee. 
THE MODE OP COLONIZATION OP CAVES. 
Not only have the Indians in prehistoric times, as is well known, frequented some of the larger 
caves (e. g., Mammoth, Salt, Wyandotte, and Luray caves), but tracks of bears, wolves, and the 
smaller mammals occur in most of the caves. In Luray Cave tracks and other marks of wild beasts, 
now exterminated from the region of the cave, occur. As remarked by Mr. Hovey: 
We saw likewise, in 1878, thousands of tracks of different kinds of animals, some of which we recognized as those 
of raccoons, rabbits, rats, and smaller creatures, while some larger tracks seemed to have been made by wolves or 
panthers. * * * We found also the bones of mice, rats, bats, a squirrel, and a raccoon. 
Mammoth, Wyandotte, Luray, and other caves are frequented by multitudes of bats, and 
though several species and genera of Arthropod parasites are found on those which take up their 
abode in caves in Europe, thus far no parasites have been discovered on'our native specimens. 
The wood-rat (Neotoma) also occurs in caves in Indiana, Kentucky, and Virginia. In fact, as is 
well known, nearly all caverns accessible from without are more or less inhabited by wild beasts, 
and in this way, either by clinging to their bodies, or by adhering to the substance they may drag 
or carry into the cave, some of the mites, false scorpions, and harvestmen may have been intro¬ 
duced from the outer world. Moreover, the species of three groups of insects which are known to 
live a more or less subterranean life in twilight, under stones or buried in the earth, may enter 
the fissures, chasms, or sink holes, and thus colonize the caverns. The genus Trechns is a sub¬ 
terranean one, its species burrowing under stones; so with the European hypogcan harvestmen, 
Phalangodes, etc., and the Myriopods. The wonder is not so much that many animals should fall 
or be carried into or voluntarily take up their abode in caves, as that they should be able to sur¬ 
vive a life in total darkness; a condition so fatal to even the lowest plant life. The fact that the 
number of cave species of animals is so small, both in Europe and America, as compared with the 
fauna of the upper world, shows how adverse are the conditions of life in such situations. This 
condition, i. e., total darkness, is the barrier that forbids a number of twilight species, such as 
Ghelifer cancroides, the cricket ( Geuthophilus stygius), Blepliaroptera defessa and other flies, Quedras, 
Polydesmus, and Lysiopetalum lactarium , Cambala annulata , and others, from becoming acclimated 
to the darkness. 
The agency of torrents passing through the sink-holes and in spring and autumn flowing 
through the lower channels, as is the case in Mammoth Cave, is clearly sufficient to account for the 
presence in the River Styx, of Mammoth Cave, of the eyed fishes which inhabit Green River, and 
of Canibaras bartoni. In this way, without doubt, individuals of Asellus communis and other out- 
of-door species of Asellus, as well as the ancestors of Dendroccelum percoecum, were transported 
into subterranean streams, pools, and wells, since they abound in the pools, ditches, and streams 
throughout the country. 
* Dr. G. Marx writes me, as these pages are passing through the press, that Count Keyserling has described from 
this cave a spider under the the name Usofila gracilis, but that the description has not yet been published hy him. 
