32 REPORT UNITED STATES ENTOMOLOGICAL COMMISSION. 



species now under consideration we are necessarily compelled to fall 

 back upon the scientific arrangement and characters of the family, sub- 

 divisions, and species. OommenciDg with the order, we will give briefly 

 the characters of the various divisions and subdivisions leading to the 

 genus Caloptenus, to which the Rocky Mountain locust belongs, omitting 

 those divisions and groups not represented in the United States, and 

 referring only to those characters which are most easily recognized, and 

 which apply specially to our acridian fauna. 



The Order Orthoptera is distinguished from the other orders of the 

 insect class chiefly by the following characters : Mouth furnished with 

 mandibles or strong biting jaws ; wings four (occasionally wanting), 

 upper pair coriaceous or parchment-like and flexible j under pair thin 

 and membranous, folding lengthwise only in plaits like a fan 5 trans- 

 formations incomplete, being active in all stages after hatching from the 



Although not as extensive as some other orders, it contains a large 

 number of species which differ very materially in appearance and charac- 

 ters, and are generally known in this country by the common names 

 earwigs, cockroaches, deviPs-horses, walking-sticks, grasshoppers, and 

 crickets. Each of these names, except the next to the last, represents a 

 distinct family of the order, thus : 



Earwigs . „ Family 1. Forficulidce. 



Cockroaches Family 2. Blattidce. 



DeviFs-horses Family 3. MantidcB. 



Walking-sticks • - ^ . . . . . Family 4. Phasmidce. 



r^ . ) Family 5. Acrididce. 



Grasshoppers I Family 6. £oc»s«id«. 



Crickets Family 7. Gri/llidce. 



As will be seen from this list, there is no confusion between the scien- 

 tific and common names until we reach *' grasshoppers ,'' among which 

 our insect belongs. Other names, it is true, are sometimes applied to 

 insects of the previous families, but with the exception of *' earwig" 

 they correspond in their application with the family limits as here given. 

 As before stated, the term " grasshopper" is applied to insects of two 

 families — Acrididce and Locustidce; but notwithstanding this difficulty 

 in using the popular name, the insects which compose the family are 

 easily distinguished from each other by prominent characters. 



Locustidce includes those species usually found on the grass, bushes, and 

 trees, which have very long, thread-like antennae, generally longer than 

 the body of the insect j the tarsi or feet are four-jointed 5 the female is 

 furnished at the tip of the abdomen with an exserted ovipositor, usually 

 more or less curved and sword-shaped j and the upper wings of the 

 .male are furnished, at the base, with a peculiar arrangement of the 

 nerves, with which, by rubbing them together, they produce sharp, shrill 

 notes. To this family belong the true grasshoppers, the katydids, and 



