September, 1941 
the ovipositor. After drilling the hole with 
the beak, the female arches the abdomen, 
stands as high as possible, then unsheaths 
the ovipositor and thrusts it forward to 
locate the place prepared. She turns her 
head under with the tip of the proboscis in 
the hole to help guide the ovipositor. One 
female was observed to make seven attempts 
before inserting the ovipositor. Most indi- 
viduals make two or three attempts before 
succeeding. After each failure, the female 
inspects the hole and works upon it for a 
time with her beak. Once insertion of the 
Ovipositor is started, the female works the 
abdomen up and down with a rapid, jerky 
motion until the ovipositor is inserted to its 
base. An alternate contraction and expan- 
sion of the abdomen then occurs while the 
egg is being worked down into position. 
This operation requires about 2 or 3 min- 
utes. The female then withdraws the ovi- 
positor and rests for 3 to 5 minutes before 
inserting the second egg. After this interval, 
she again locates the hole by means of anten- 
nae and beak and then repeats the operation 
of inserting the ovipositor. In some cases 
only one egg is laid in a place, but two eggs 
appear to be the normal number for this 
species. 
The number of eggs laid varies with the 
individual from day to day. One female was 
observed to oviposit in six different places 
between 10:00 a.m. and 12:00 o’clock noon. 
This same female was observed to oviposit 
daily from June 23 to 27, but died on June 
iy 
The apple redbug, Lygidea mendax Reu- 
ter, breeds on hawthorn and apple; it ma- 
tures a week to 10 days later than Hetero- 
cordylus malinus. In 1914, at Batavia, New 
York, the majority of females matured 
about June 20. Several females were 
watched closely but no eggs were obtained 
until July 8. When ready to lay, the female 
moves about over the twigs, searching for 
lenticels on wood of the previous year’s 
growth. She drills the lenticel by means of 
the proboscis. One female required 10 min- 
utes for this operation. She failed in three 
attempts to insert the ovipositor but on the 
fourth she succeeded. She took 214 minutes 
to lay the egg. After an interval of 4 min- 
utes, she returned to the hole and upon the 
second trial inserted the ovipositor and laid 
an egg. She then sealed the wound by means 
of the proboscis. The lenticels are normally 
light colored but, after being injured by the 
KNIGHT: PLANT Bucs, or MirIpAg, oF ILLINOIS 3 
process of oviposition, they appear reddish 
brown. The eggs are placed in the cambium 
at such an angle that the lower ends rest on 
solid wood and their tips are 1.5 mm. apart. 
Females of this species were observed ovi- 
positing on trees in an orchard as late as 
July 18. 
The pear plant bug, Neolygus communis 
Knight, oviposits in the cambium of pear 
twigs. The actions of the female are very 
similar to those of the species described 
Fig. 2.—Egg of Paracalocoris colon, shown 
in cross section of new growth of apple bark. 
Adapted from Knight (1915). 
above. Examination of one oviposition point 
revealed that six eggs had been laid in a 
space 1.0 mm. long. The eggs were closely 
packed in a double row lying flat just within 
the cambium layer. Eggs measured were 
1.05 mm. in length by 0.26 mm. wide. 
An apple mirid, Paracalocoris pallidulus 
McAtee, was found to lay eggs only where 
dead wood was available. Females that 
were caged on limbs free from scars and 
dead stubs did not oviposit. Four females 
were observed to lay when placed on branch- 
es having dead stubs. Five eggs were placed 
around the margin of one stub, a new hole 
being made for each egg. The egg of this 
mirid differs from those of several species 
at least in having a white cap with two 
keels that curve up and nearly meet over the 
top of the egg, fig. 2. The egg cap projects 
from the cavity as shown in the figure but 
is not conspicuous because of the uneven 
character of the rough bark and surrounding 
wood. Eggs laid in July remain until the 
following spring before hatching. 
A majority of mirid species produce only 
one generation per year, but a few have been 
