OF ARTS AND SCIENCES : DECEMBER 10, 1862. 87 



Insect Tracks. 



Though the Ichnologj does not undertake to distinguish between 

 the tracks of Insects, Crustaceans, and Myriapods, yet it describes six 

 species that had six feet with single linear extremities, and we can 

 hardly doubt that these were insects. It also describes in the same 

 group six other analogous species, some of which had apparently 

 only two and others four feet. Yet on one or two specimens there 

 appeared, occasionally at least, tracks of at least a second set of feet ; 

 and the suggestion was made, that probably they had the six feet of 

 insects, but only two or four of them usually left an impression. 

 Several specimens recently obtained completely confirm this view. It 

 is exceedingly probable, then, that at least fourteen species of insect 

 tracks are described in the Ichnology. To these may be added two 

 new ones, which follow, one of which seems to be a new genus. 



16. BiFURCULAPES CDRVATus. The tines of the fork are so curved 

 here as to be distinctive of a species. 



17. Harpepds capillaris. The principal feet are beautifully 

 curved, and the mud at the larger end of the track is crowded into 

 a bunch, that may be regarded as a short handle to the sickle {ap-nrj, 

 a sickle). The curve of the sickle is as fine as a delicate hair: hence 

 the specific name. 



The other fourteen species are the following (see Ichnology) : — 



AcANTHICHNUS CURSORIUS. HeXAPODICHNUS MAGNUS. 



a. saltatorius. h. horrens. 



a. tardigradus. bifurculapes laqueatus. 



conopsoides larvalis. b. tuberculatus. 



Grammepus erismatus. B. scolopendroides. 



lithographus hierogltphicus. b. elachistotatus. 



l. cruscularis. copeza triremis. 



If these conclusions are correct, they show the presence, during the 

 Connecticut Eiver sandstone period, of numerous insects, and thus the 

 probability is increased that this rock is Jurassic rather than Triassic ; 

 for of the species of fossil insects described by Bronn, only nine occur 

 below the oolite, and one hundred and nineteen in that formation. 



Peculiar and Undetermined Specimens. 



18. SCALICHNUS INCERTUS. 



These impressions are very distinct ; and if we look only at the 



