14 BULLETIN 256, U. S. DEPARTMENT OF AGRICULTURE. 
larly bad in 1911 and 1912 large numbers of adult katydids disap- 
peared in August and September. At about the same time large 
numbers of small birds of an undetermined species were noted in 
and about these orchards. These little birds were unquestionably 
responsible for the disappearance of katydids. 
Seasonal History. 
As there is but one generation of the fork- tailed katydid annually, 
the duration of the life cycle is approximately one year. The aver- 
age life cycle, as determined from a number of complete rearings in 
1911 and 1912, was 367 days, ranging from 343 to 383 days. The 
first nymphs to appear issued about April 20, the majority issuing 
during May. Nymphs are most abundant in May and June, but 
have occasionally been seen as late as August 15. The first adults 
appear early in June, are fairly numerous by the last of June, and 
most abundant during July and August. They can be found with- 
out much difficulty in September and more rarely in October. The 
last specimens of the season were captured December 3. A few 
have been kept alive in screen cages until early January. 
THE ANGULAR- WINGED KATYDID. 
NATURE AND EXTENT OF INJURY. 
The angular-winged katydid ( Microcentrwn rJiombifolium Sauss.) 
somewhat closely resembles the fork-tailed katydid and is closely 
associated with the latter on orange trees in the San Joaquin Valley. 
It is, however, larger than the fork-tailed katydid and may be readily 
distinguished from that insect by its size, broader wings, and in the 
nymph by its hunchbacked appearance. Although responsible for 
a certain amount of injury to orange trees annually, it attacks only 
the foliage and rarely does enough damage to cause alarm. This 
insect has been present in Florida orange groves for years without, 
except in rare cases, causing sufficient damage to attract attention. 
This is also the case in California. The observations of the writers 
indicate that the minor position of the angular-winged katydid as a 
pest is largely due, first, to the high percentage of parasitism suffered 
by the eggs; and, second, to the fact that the insect does not attack 
the fruit. That it might injure the fruit if able to increase to the 
point of crowding is quite possible. The insect is also exposed to 
the attacks of various enemies, chiefly birds, because of its large size 
and slowness of movement. The first-instar nymphs feed principally 
if not wholly upon the leaf surface, removing merely a chlorophyll 
layer. Later stages gnaw clear through the leaves, filling them with 
ragged holes, and destroy a larger amount of foliage in proportion 
to their number than does the fork-tailed katydid. The insect has 
never been seen to attack blossoms or fruit. 
