48 PROCEEDINGS OF THE NATIONAL MUSEUM vol.68 



distinct median carina. Mesopleiira coriaceous with a smooth area at 

 upper hind margin, sloping backward so that anterior legs are wide- 

 ly separated from second and third pairs. Hind tibia longer than 

 tarsus, claws simple. Wings ample, hyaline, pubescent, ciliate, veins 

 brown, first abscissa of radius arcuate, second nearly straight, radial 

 cell five times as long as broad at base, areolet reaching one-fifth way 

 and cubitus to the basal. Abdomen shorter than head and thorax, 

 length to height to width as 17 : 15 : 9, lengths of tergites along dorsal 

 curvature as 35 : 12 : 12 : 4 : 5 : 8, second bare at base. Ventral valves 

 oblique, tip of ovipositor straight, ventral spine directed horizon- 

 tally, slender, in side view three times as long as broad. Using width 

 of head as a base the length of mesonotum ratio is 1.3, antenna 2.5, 

 ovipositor 1.8, wing 4.4. Length, 1.6-2.2 mm. Average of 200 meas- 

 ured specimens, 1,85 mm. 



Types.— Qdit. No. 27198, U.S.N.M. Type and 99 paratypes. Para- 

 types at American Museum, Field, Harvard, Stanford, Philadelphia 

 Academy, California Academy, British Museum, Paris Museum of 

 Natural History, and with Professor Tavares. 



Host.—Quercus suber., the European cork oak introduced into 

 California. 



Gall (fig. 10). — Cells imbedded in the wood immediately under 

 the normal bark on small slender twigs, sometimes occurring in 

 such great numbers that the twig is uniformly hypertrophied to 

 twice its normal diameter for several inches. The individual cells 

 are elongated, 2.5 mm. long b}^ 0,7 mm. in diameter, lying parallel to 

 the axis of the twig, the exit hole through the bark 0.5 mm. in 

 diameter. 



Habitat. — The tj^pe is selected from material from a cork oak 

 tree on the grounds of the Cottage City Nursery Co., north of San 

 Jose, Calif. Paratype locality, Pasadena. 



Biology. — When the San Jose tree was visited in company with 

 Dr. H. E. Burke on May 16, 1918, it was almost in full bloom, the 

 young leaves not yet half grown. Some of the cells were in the 

 previous season's growth but most were in the two-year-old wood 

 and a few in that still older. Almost every twig on the tree Avas 

 more or less infested. When badly infested so as to be hypertro- 

 phied the twigs are killed and fully half of the small tAvigs in 

 the upper part of the tree seemed to be dead. No other kind of 

 gall was seen on the tree. A fcAv adults had already emerged and 

 were seen resting on the foliage but most were still in the pupa 

 state. From twigs collected on that date and sent to the Eastern 

 Field Station for rearing (Hopkins U. S. No. 15G08«) adults emerged 

 May 21 to June 5. Adults emerged at Evanston June 3-11. This 

 tree had a trunk diameter of about 15 inches but nothing Avas 

 learned as to its histbrv. 



