600 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
like kernels containing the gall-wasp larvae. Adults emerge early in 
the summer and oviposit in immature acorns. The acorn pip galls 
of the agamic generation develop in the acorn cup, usually with an 
aborted acorn. The gall is shaped somewhat lke an incisor tooth. 
From one to five or six may occur in a single cup, and they range in 
size from that of a flaxseed to 14 inch in ‘length. The gall may be 
important when abundant because of acorn and ament destruction. 
At the present time the insect, although not rare, does not seem to be 
numerous enough to constitute a seed problem. If control is desired, 
collect and destroy the fresh galls. 
ROOT GALLS 
Bassett (24) described Callirhytis radicis Bass. as the agamic form 
of Callirhytis futilis O. S., which is a common gall on leaves of white 
oak (Quercus alba) in Connecticut. C. radicis forms globose, grayish 
root galls about 3 by 41% inches, just below the ground surface on the 
main roots of young white oak. The bark is covered by a mass of 
blisterlike swellings and below the surface numerous larvae of all 
sizes may be found early in the spring. The adult gallflies appear 
about the first of July. 
SuBFAMILY. SYNERGINAE 
The Synerginae are almost entirely inquilines. They are often 
mistaken for true gall makers, to which they frequently bear an ex- 
tremely close resemblance. They usually lay their eggs in cynipid 
galls on oak, but have also been reared from galls formed by Diptera 
and other insects. 
SuspraMILty IBALIINAE 
The Ibaliinae are a very small group quite distinct from other 
Cynipinae, and some authorities consider them a separate family. 
The members are all true parasites that attack larvae of the Szricidae. 
[balia maculipennis Hald. is a fairly common species in the eastern 
half of the United States. The adults are about 1% inch long and 
strikingly marked with a yellow and dark-brown pattern. The fore- 
wings have two conspicuous fuscous bands. Weld (428) reported 
the capture near Evanston, IIl., of a large number of specimens which 
were oOvipositing in hickory trees that had previously been killed 
by bark beetles. The /balia adults were thrusting their ovipositors 
into the tunnels formed by horntail larvae. The observer believed 
that the egg was deposited in the tunnel, and, after hatching, the para- 
site larva probably crawled along until it found its host. Full-grown 
Lbalia larvae were found in the spring in burrows they evidently had 
made for themselves after they had finished feeding. Pupation took 
place in these burrows and adults emerged about June 1. Chrystal 
(92) gives a detailed account of the biology of Lbalia leucospoides 
Hochenw. in England. This species is a ‘true internal parasite of 
the wood wasp Sirex cyaenus F., which infests larch, the parasite’s 
eggs being deposited in either the host’s egg or the newly hatched 
Sirew larva. Shipments of this species have been made from Eng- 
land to New Zealand for liberation against Sirex juvencus L., which 
is very destructive there in plantations of Pinus radiata. 
