434 NOTES. 



true spiders in fissures in blocks of coral which were under water at 

 every high tide ; they were very common in Bohol and at Zamboanga 

 in the Philippines, but as yet remain undescribed, for my collection of 

 Arachnida is in the Hamburg Museum, and has not been worked 

 upon. 



3. Insccta. Darwin, in his well-known Naturalist's Voyage, alludes 

 in many places to marine insects, principally beetles and bugs. Many 

 insects have lately been discovered on the coast of North America by 

 Baird (Rep, on the Condition of tJie Sea-fisheries of the South Coast of New 

 England, 1871-2, p. 1) and Packard (Proc. Essex Inst. vol. vii.p. 44, and 

 Sillimari's Journal, 1874, p. 181). These are beetles, bugs, and flies. I 

 found a few marine insects in the Philippine seas, but they unfor- 

 tunately remain undescribed. Of older observations I may mention 

 Slabber's dipterous larva, probably the larva of a species of Chironomux ; 

 and I found an abundance of a very similar species in the Philippine 

 seas, where swarms of flies sometimes cover the surface in still bays ; 

 then Audouin, who observes that Blemius fnlresccna surrounds itself, 

 like the fresh-water Argyroneta, with a bubble of air. Among the 

 Hemiptera Salda, Corixa, Hygrotrechus, and Ha-lobates the species of 

 Halobates are most conspicuous, for they are found in every stage of 

 development running about on the surface of the sea, often hundreds 

 of miles from land . Eight species of the genus, as I am informed by 

 my friend Dr. Hagen, have been described ; that described in the text 

 and discovered by me is a new species and the largest of all. They are 

 found in the Atlantic, Indian, and Pacific Oceans, as well as in the 

 Chinese Sea, but only in tropical or subtropical regions. 



Insects are also found in salt-water lakes inland. Packard found 

 eight different species in Clear Lake (Silliman's Journal, 1871) and one in 

 Lake Mono. Numerous insects exist in the brine lakes of Europe, but 

 no collection or complete description of them is known to me. I experi- 

 mented this year on some larvas of flies which I found in a basin in the 

 courtyard of the Wiirzburg University ; they lived in sea- water very 

 happily for five or six days, but then perished. I suspect, however and 

 shall test it more accurately next year that they died for want of food. 

 Compare with this Plateau's experiment ; see below. 



Molhisra. Cyclas, Unio, and Aiwdonta live in the Livonian Gulf 

 associated with Tellina and Venus. In the Baltic we find Lymncca 

 aiiricularia and oi-ata, and Nei itina fluviatilit with marine mollusca. 



Paludina and Neritina are found in the Caspian with Mytilus and 

 Cardium, according to Eichwald. 



Planwbis glaber (Jeffreys) is found in 1,415 fa' horns north of Cape 

 Tenez, Algiers. 



Unio sp., within reach of the salt-water flow in Brisbane river; 

 (Voy. of Rattlesnaltc, vol. ii. p. 362). Baer found Unio at the mouth of 

 the Dwina. 



