OF WASHINGTON. VOLUME XIII, 1911. 143 



Owing to the varied habits of different families and genera 

 of the musical Orthoptera, somewhat different methods may 

 be followed in a study of their stridulatious. Among the 

 acridiiaus two distinct methods of stridulatiou prevail. Some 

 species stridulate while at rest, rubbing the inner surface of 

 the thigh against the outer edges of the tegmina. Other 

 species stridulate only during flight. Those grasshoppers 

 which stridulate while at rest may readily be captured and 

 confined in boxes, together with a little grass or herbage. In 

 this way the stridulations of these insects may easily be de- 

 termined, although in the field many species are shy and diffi- 

 cult to approach. Those acridiians which produce their char- 

 acteristic notes only during more or less extended flights must 

 be studied entirely in the field, since to confine them would 

 prevent this freedom of flight by which their stridulations are 

 produced. Nearly all our acridiians are strictly terrestrial and 

 stridulate entirely by day. For these reasons these insects 

 are less difficult to approach and observe than other Orthop- 

 tera of more arboreal habits. 



Among the Locustidae, many are strictly arboreal and can 

 be approached only with great difficulty, owing to almost in- 

 accessible positions among the foliage of trees. 



The species of Scudderia are more or less terrestrial in their 

 habits, dwelling among the tall grasses and low herbage. 

 Some species stridulate onlv at long and irregular intervals, 

 usually at night. The stridulations of these katydids are best 

 studied by confining them in a room, placing them on a bough 

 or bunch of grass by the screened window. In this way the 

 notes of any individual are readily obtained as soon as dark- 

 ness comes on, and it hears its fellows stridulating outdoors. 

 I have found it more convenient to confine some nocturnal 

 species of Scudderia in my sleeping-room, together with an 

 abundance of the proper plants among which to conceal 

 themselves. In this way I was afforded a chance to record 

 any sounds which might be produced only at long intervals 

 throughout the night. 



The species of Amblycorypha are best studied by confining 

 them on herbage in one's sleeping- room, since these insects are 

 almost strictly night singers, and very persistent in their 

 strident calls. Even in the field these katydids are confined 

 almost entirely to the low herbage of the fields and roadsides- 

 so that they are readily approached. Amblycorypha oblovgi- 

 folia De Geer is a most persistent singer during confinement. 



The species of Microcentrum also stridulate freely when 

 confined in a room. The big, noisy katydid Micro centrum 



