288 
Psyche 
[September 
needle of a sound level meter is not deflected fully by it. However, 
a strong chirp seems to peak at 50 db at 4" on the A and B scales. 
[All readings use a reference level of o db = 0.0002 microbar, 
alt. 9500 ft., and the scales used are those recommended by Peter- 
son and Gross (1963) for the given sound level and frequency.] 
Males can usually detect a female as a female from at least two 
feet and spurt-run toward her emitting separated high intensity 
chirps as above. Figure 7 illustrates the general schema of 
courtship of receptive and non-receptive females. The female “signal” 
seems to be an inadvertent movement such as feeding, walking, 
grooming or no movement at all. Her greater size probably also is 
a sign stimulus. The male chirps vary from pulsed phrases of one 
to five chirps in succession. When he has approached within one inch 
of the female, he typically orients by facing her directly, frons to 
frons. The two grasshoppers “fence” mutually with their antennae 
and the male continues chirping. The male then moves to the 
female’s side and faces her thorax. He may chirp and he may even 
butt his frons against the side of the thorax. The male finally places 
a prothoracic tarsus on her metathoracic femur, pats the substrate 
with his hind tarsi several times very rapidly and then attempts to 
mount from the rear of the female. Simultaneously, there often is 
a train of 4-5 chirps just before mounting. 
Females seem to be sexually responsive as virgins 10 days after 
molt and again after laying the first egg pod. However, these data 
are derived from females that were group-isolated as nymphs until 
presentation of the males and it has been shown by Highnam & Lusis 
(1962) that isolated females of Schistocerca gregaria mature more 
slowly. We considered a female receptive if copulation was completed. 
Some females actively solicited attention by males. After the short 
bout of antennal fencing initiated by mutual orientation and approach 
by both male and female^ the female often turned while the male 
chirped, presented her side to the male, lowered the near hind leg 
and raised her opposite leg and both tegmina, exposing the whole 
abdomen. The valves of the ovipositor may open or at least move 
a bit. At this point three females of the total of 20 successful court- 
ships observed fluttered the hind femoro-tibial joint against the 
ground but not high enough to contact the tegmen. After this the 
male gave his final burst of chirps and mounted. In one case, in 
which an old male of four weeks was involved, the female initially 
followed the male and patted his wing tip with a fore tarsus, while 
he ran away from her giving the male flutter-rasp ( q.v .). Then he 
