October 20, 1893.] 



SCIENCE. 



215 



Evidence is continually increasing that in different 

 coral-growing areas different processes have gone on and 

 that since all coral islands have not been made in the 

 same way no single, all-comprehensive theory is possible. 



Dr. Guppy found at the Solomon Islands that, adjacent 

 to the shore, corals grev vigorously, whUe outside of this 

 zone there was a space where debris from the shore so 

 fouled the water that no corals grew, while still farther 

 out they grew finely. It is easy to see that the first zone 

 would make a fringing reef, the zone affected by debris 

 would be open water, and the outer zone a barrier reef, 

 and thus these varieties of coral formation be produced 

 without the conditions of either theory. Nor is it at all im- 

 probable that other methods of coral island making may be 

 discovered as further investigations reveal new facts, and, 

 while it may be regarded as most probable that Mr. Mur- 

 ray's theorj' will be held sufficient to explain the larger 

 part of the coral formations of the globe, it is also jjroba- 

 bable that Mr. Darwin's views wUl never be wholly set 

 aside, but will always be needed to account for extensive 

 groups of reefs and islands, while here and there all over 

 the region of coral island making there will be found 

 phenomena which require other explanation because of 

 special peculiarities. 



THE PROTECTION OF OUR WILD PLANTS AND 



ANIMALS. 



BY JOHN GIFFORD, SWAETHMORE COLLEGE, PA. 



A FEW years ago an association for the protection of 

 plants was founded in Switzerland at Geneva. Tourists, 

 and even botanists, were guilty of such vandalism that 

 many feared the extermination of certain rare plants. By 

 the dissemination of seeds and other means, however, 

 many species have been protected by this society in 

 Switzerland and elsewhere. 



Although we have forestry associations in this country 

 we have as yet done nothing toward the protection of rare 

 plants. 



In south Jersey, for instance, there are many unusual 

 and beautiful species, but ovring to the action of winds, 

 fires and voracious botanists they are becoming gradual- 

 ly scarcer. 



Along the beaches of the seashore the forests are 

 destroyed for the building of resorts, in other places they 

 are buried by moving sand dunes. The Schizcea pusilla 

 is a little fern, which is not found elsewhere in the "United 

 States. It grows in three or four isolated patches in the 

 low pine barrens of south Jersey. One patch has already 

 been almost wholly destroyed by forest fires, and from 

 the others hundreds of specimens are carried away by 

 greedy botanists every September. The extinction of 

 this species is only a question of a very few years. 



This applies to almost every locality in the United 

 States. There are few places which cannot boast of a few 

 rare species. 



The writer knows of one instance where a class of young 

 botanists exterminated a patch Aplectrum Memale, in a 

 region where it was very rare, by eating the corms. 



In spite of game protective societies, owing to the 

 thoughtlessness of sportsmen, many of our wilcf animals 

 have disappeared. A few deer still linger in the pines of 

 south Jersey, but every season their number is remark- 

 ably lessened. Had they a place of refuge where they 

 could always remain unmolested, their extinction could be 

 prevented. 



It is hoped that the Government may set aside in every 

 state a tract of guarded laud. A few acres showing the 

 nature of the country in the wild state will be appreci- 



*See Westwood's Modem Classification of Insects on Larval 

 Mycetophilidce. 



ated more in years to come than at the present time. 

 There the trees may remain untouched, there remarkable 

 and unusual plants may grow in safety, and there the wild 

 animals may find a refuge. The advantages of such a 

 scheme are too numerous to mention. The. retaining of a 

 typical portion of each kind of territory in every state, 

 together with its plants and animals, guarded every day 

 of the year, would not only delight the naturalists and 

 lovers of nature, but would insure at least a small portion 

 of forest country here and there, which tends to lessen in 

 many ways the destructive forces of nature. 



Dr. Charles Dolley and others of the American Associa- 

 tion for the Advancement of Education have arranged to 

 collect and preserve on their property at Avalon all the 

 plants peculiar to the beaches of the Jersey coast. This 

 is one of the objects of the association, and it hopes to 

 control some land in the low pine barren region where no 

 man will be allowed to botanize or hunt. 



SILK SPINNING FLY LAEV^. 



BY H. GASMAN, LEXINGTON, KY. 



In a brief paper printed in Science recently a silk spin- 

 ning cave larva was described by me and referred to the 

 order Diptera. Its general appearance and its habit of 

 making a thread are features in which it approaches the 

 larvEe of Lepidoptera, a resemblance which has been com- 

 mented on by others in conversation with me since. Yet 

 the larva in question is unmistakably Dipterous, and it 

 was part of my object in publishing the note to call atten- 

 tion in an indirect way to the fact long, but not very gen- 

 erally, known,* that larvse of certain flies approximate the 

 Lepidoptera, in spinning silken threads. In saying that 

 they produce silk, I wish, however, to be understood as in 

 no way implying that the threads have the exact chemical 

 and physical properties of the silken fibres made by the 

 silkworm. They are silk from the biological, not from the 

 commercial point of view. They are produced by special 

 glands differing little, if at all^ from the sUk glands of 

 other insects, are employed by these larvas for a purpose, 

 and are not consequently to be compared with the trail of 

 slime left by a slug or worm. 



Fig. 1. 

 My attention was first attracted to such larvae while 

 making examinations of Kentucky caves. I have, how- 

 ever, been long familiar with other larvse belonging to the 

 same order, which habitually spin threads having a very 

 important relation to their welfare. In small streams in 

 McLean County, Illinois, occurs a larval Simulium which 

 produces such threads. Another species is extremely 

 abundant in rills in eastern Kentucky, where the rocks 



