﻿AMERICAN CYNIPID GALL WASPS — WELD 335 



which are two indistinct smooth pits. Carinae on propodeum ahnost 

 straight, widely diverging below. Mesopleuron striate below, coria- 

 ceous above. Hind tibia longer than tarsus. Claws simple. Abdo- 

 men as long as head plus thorax, gibbous below petiole, all tergites 

 visible on dorsal margin, ventral spine 6.5 times as long as broad in 

 side view, ovipositor straight at tip. Using width of head as a base 

 the length of mesonotum ratio is .67, antenna 2.7, ovipositor 5.9. 

 Length 1.5-2.65 mm. Average of 42 specimens 2.2 mm. 



Differs from Z. sphaerula Weld in its smaller size, in having mesoscu- 

 tum uniformly convex in profile, the mesopleuron striate in part and 

 ovipositor straight at tip. 



Types. — U.S.N.M. No. 60122 : Type and nine paratypes. Paratypes 

 also in A.M.N.H., C.M.N.H., A.N.S.P., C.A.S., and the M.C.Z. 



Host. — Querciis palu.strU. 



Gall (pi. 16, fig. 12). — Almost spherical, smooth, bare, with purple 

 spots on a cream background, attached singly on under side of leaf 

 on a secondary vein, dropping in early October. From 1.4 to 2.5 mm. 

 in diameter. Pure white inside with the minute larval cavity central. 



Habitat. — Type locality East Falls Church, Va. Galls were col- 

 lected in October in eight different years ; adults emerged the second 

 spring in each case on the following dates: March 6, 20, 25, 29, April 

 1, 3, 7. Buds on pin oak at that time show no signs of swelling. Ovi- 

 position not observed. Alternating generation unknown. 



Genus EUMAYRIA Ashmead 



EUMAYRIA INVISA, new species 



Female. — Light brown to amber. Head massive, coriaceous, dull; 

 from above broader than thorax, occiput not concave ; from in front 

 broader than high, malar space one-third eye without groove, antennae 

 14-segmented, fii-st four as 13 : 8 : 20 : 14. Pronotum coriaceous, dull. 

 Mesoscutum lighter in color, somewhat shining, not quite smooth, 

 rather flat, parapsidal grooves percurrent, straight and converging be- 

 hind but well separated at scutellum. Disk of scutellum margined at 

 sides, narrowed in front, rugose behind. Wing reduced, not reaching 

 tip of abdomen, pubescent and ciliate, venation almost normal, areolet 

 wanting. Mesopleuron with a smooth and polished spot under hind 

 wing. Claws simple, hind femur short and stout. Carinae on pro- 

 podeum almost straight, slightly converging above. Abdomen longer 

 than head plus thorax, tergite II with usual patches of pubescence at 

 base, rest subequal. Ventral spine longer than hind metatai'sus, eight 

 times as long as broad in side view. Using width of head as a base the 

 length of mesonotum ratio is 1.0; antenna 2.3; wing 2.0. Length 2.3- 

 3.2 mm. Average of 12 specimens 2.56 mm. No other species known 

 with reduced wings. 



