KATYDIDS INJURIOUS TO ORANGES IN CALIFORNIA. 
9 
-The fork-tailed katydid: Fourth-instar nymph, 
natural size. (Original.) 
About three times 
are faintly visible in the forewings. The pronotum covers about one- 
half the dorsum of the mesothorax. The sexes can be distinguished 
in this stage by the appearance of the external genitalia. Just after 
the third molt 
the nymph is 
about two-fifths 
inch long. 
Fifth instar (fig. 
9). — Measure- 
ments: Length 
of body, 12.5 
mm.; pronotum, 
3 . 1 mm . ; pos- 
terior femur, 13 
mm . ; antenna, 
26 mm. In this 
instar the posi- 
tion occupied by 
the wing-pads is different from that in any of the earlier instars. 
They now lie partly over the abdomen in a tectiform position, this 
change being brought about by the previously outwardly exposed 
sides being brought out, upward, and in leaving the inner sides 
exposed roof-shape above the body. The tips of the posterior 
wing-pads now reach to the hind margin of the second abdominal 
segment; wing-pads similar in shape, in position relative to the body, 
and in venation to 
the adult wings. 
Pronotum complete- 
ly covering the dor- 
sum of the meso- 
thorax. The young 
of this instar are 
about one-half inch 
long shortly after 
the molt. 
Sixth instar (fig. 
10) . — Measurements : 
Length of body, 16 
mm.; pronotum, 4.5 
mm.; posterior fe- 
mur, 18.5 mm.; an- 
tenna, 3.9 mm. In 
this instar the nymphs resemble adults in almost every particular 
except the smaller size of the wings. Just after molting the wings 
extend rooflike over the abdomen to the ninth segment, the dorsal 
93417°— Bull. 256—15 2 
/ f 
/ 
Fig. 9.— The fork-tailed katydid: Fifth-instar nymph 
times natural size. (Original.) 
About three 
