21 



between investing tunics, lies a closely coiled spiral thread; and out- 

 side of and enveloping -whicli is the peritracheal vessel, ■whose outer 

 walls are not limited by the extent of the tracheae proper, but ex- 

 tend beyond the spiral coil to form the second and distinct part of 

 the system, — namely, capillary tubes, penetrating every portion and 

 organ of the body, and terminating in a mesh-work of interlacing 

 branches. In other words, this portion of the circulator}' system 

 consists of branching tubes, which enclose within all but their ulti- 

 mate ramifications the similarly branching tubes of the respiratory 

 system. The fluids, therefore, forced by the dorsal vessel into the 

 peritracheal cavities, become thoroughly aerated before passing into 

 the tissues of the body to perform their functions ; when they have 

 done their work they empty into the general cavity of the body, and 

 mingling with the fluids newly expressed from the alimentary canal, 

 join the general currents which, as first shown by Cams, appear to 

 set, in regular channels at the sides and floor of the body, often, 

 however, with no vascnlar boundaries, toward the hinder extremity 

 of the body, or toward the sides of the dorsal vessel, to enter again 

 the initial point of the circulation. 



The Florida Orthoptera collected by Mr. J. H. Comstock. 



As no attempt has yet been made to tabulate the Orthoptera from 

 any district in the southern United States, it has seemed desirable, in 

 naming for Mr. Comstock the species collected by him in the spring 

 of 1876, to print a list of them, with descriptions of those which 

 prove to be new. The collection was made almost entirely at two 

 localities — Jacksonville on the St. Johns, and Fort Reed in Orange 

 Co., about three miles south of Mellonville, at the head of naviga- 

 tion on the St. Johns. So far as I am aware, no collections of any 

 importance have before been brought from the upper St. Johns, so 

 that this portion of the collection, and the larger one, has more than 

 ordinary interest. A few notes sent me by Mr. Comstock are ap- 

 pended under the species to which they refer; and occasional notices 

 of captures by others in other parts of the State, or of neighboring 

 States, are added. The Collection is in the Museum of Cornell 

 University. 



Gryllides. 



Gryllus assimilis (Fabr.) Goeze. Id, 1 ?, found under 

 boards on the beach near Sanford, April 6 ; 1 ? , Ft. Reed, April 

 21; 1 ?, Jacksonville, May 6. This agrees altogether with Saus- 

 sure's description of the small black United States form of the spe- 

 cies, excepting that the wings extend no further back than the tips 

 of the cerci. 



