190 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.59. 



occurs on any other oak in that region, so that finding one of these 

 galls the identity of the oak is known at once. A few of these galls 

 occur on a rare oak in southern Arizona and a few on an oak on the 

 Channel Islands, showing, were botanical evidence not at hand, the 

 close relationship of these local and isolated oaks. It is no uncommon 

 thing to find herbarium sheets of oaks wrongly determined, the 

 evidence being a gall accidently included. There is one American 

 oak on which no Cynipid galls have yet been found. The author 

 hopes at some time to be able to make a contribution to the botany 

 of the oaks based on field observations on the galls. 



SYNOPSIS OF SUBTERRANEAN CYNIPID GALLS ON OAK. 



1. True root galls p. 190. 



2. Underground woody stem swellings, ploythalamous, cells under bark p. 190. 



3. Cells in the thickened bark at crown of tree p. 191. 



4. Detachable galls at crown p. 191. 



1. Galls on the true roots. 

 On small fibrous rootlets: 



Single or few in cluster, brown, ellipsoid, 5 mm. in diameter, under large tree in 

 forest, 1-5 cm. underground. Q. bicolor ..27. CallirhytisellipsoidaV\ T e\d,-p. 227. 



Similar but on Q. alba 28. Callirhytis elliptica Weld, p. 228. 



On roots 5-15 mm. in diameter: 



Large brown woody, single or agglomerated into irregular masses as big as a man's 



fist. Q. stellata 14. Odontocynips nebulosa Kieffer, p. 210. 



Similar to above but on Q. lyrata and Q. virginiana. 



Probably No. U. See note, p. 211. 



Fleshy, fig-shaped, white, in clusters, in spring, drying to a dark brown mass. 



Q. virginiana, geminata 35. Belonocnema treatae Mayr, p. 238. 



2. Underground stem swelling, woody, polythalamous, cells under bark, which Is 



not greatly thickened. 



Large abrupt swelling covered with normal hark, at base of sprouts or on small sap- 

 lings. Q. agrifolia,, californica, wislizeni 41. Weld No. 1501, p. 243. 



Abrupt, irregularly rounded, 1-3 cm. in diameter, brown, Q. velutina, marilandica, 

 texana 29. Eumayria Jloridana Ashmead, p. 230« 



Similar in size and shape but perhaps fleshy when fresh. Terminal on etiolated 

 sprouts of a deciduous oak in stone pile or under humus, in Colorado, New Mexico. 

 Arizona 38. Weld No. 706, p. 242. 



Similar gall on Q. emoryi 39. Weld No. 707, p. 242. 



Slight one-sided enlargement on stems 1 cm. or less in diameter. Cells thin-walled, 

 nested under bark. Adults found in September. Q. fendleri. Colorado, New 

 Mexico 33. Compsodryoxenus tenuis Weld, p. 235. 



Similar on larger stems of Q. gambelii. Adults found in April. Colorado. 



30. Bassettia tenuana Weld, p. 232. 



Slight spindle-shaped enlargements at base of current year's shoots, in fall. Cells 

 not twice as long as broad, not nested but scattered. Q. chapmani, stellata. 



34.. Compsodryoxenus humilis Weld, p. 236. 



Similar in external appearance but cells elongated, at least twice as long as broad 

 placed lengthwise. Q. chapmani 31. Bassettia Jloridana Ashmead, p. 233 





