ART. 19. GAIJl^FLIES OF THE FAMILY CYNIPIDAE WELD. 25 



with the acorns, and it is these that are commonly observed and col- 

 lected and which fail to yield the maker. 



CALLIRHYTIS MIDDLETONI, r.ew species. 



Plate 5, fig. 19. 



Female. — Pale reddish-brown, head and legs inclining to buff, tips 

 of antennae, anterior and parallel lines, foveae and propodeum more 

 or less infuscated. Head narrower than thorax, coriaceous, short 

 pubescent except above antennae ; seen from above twice as broad as 

 long; seen from in front interocular space .57 transfacial and area 

 1.55 times as broad as high, malar space .55 eye and with groove, 

 antennocular not quite equal to ocellocular, postocellar greater than 

 ocellocular, mandibles 2-toothed, palpi 5- and 3-segmented, antennae 

 14-segmented, lengths in balsam as 23 : 10 : 28 : 22 : 18 : 17 : 14 : 12 : 11 : 

 11: li: 10: 9: 14, first stoutest, ilagellum only slightly stouter 

 toward apex. Thorax covered with short close-set pubescence not 

 hiding sculpture. Mesoscutum broader than long, coriaceous, parap- 

 sidal grooves straight, dull, with transverse ridges, obliterated an- 

 teriorly, trace of median posteriorly, antenna and lateral lines dis- 

 tinct. Scutellum rugose, pits large and smooth, triangular impres- 

 sions on sides. Carinae on propodeum straight for two-thirds their 

 length and converging slightly above. Hind tarsus shorter than 

 tibia, second shorter than fifth, claws simple. Wing subhyaline, 

 veins beyond second cross-vein faint, apical abscissa of subcosta a 

 mere spur like the one at angle of first abscissa of radius, areolet 

 indistinct, clear spot above costal hinge, surface pubescent, margin 

 not ciliate. Abdomen longer than high, slightly compressed, second 

 tergite occupying four-fifths with large pubescent areas on side?}, 

 ventral spine horizontal, prominent, tapering, ovipositor when dis- 

 sected out longer than antenna. Using width of head as a base the 

 length of mesonotum ratio is 1.3, antenna 2.1-2.8, ovipositor 2.2-3.0, 

 wing 3.5-3.6. 



Length of 36 pinned specimens 3.5-4.1 mm. Average 3.8 nmi. 



Type.— C&t. No. 22910, U.S.N.M. Twenty-five cotypes. 



Host. — Quercus fhellos Linnaeus. 



Gall. — Green, 6 by 7 mm. and 5 mm. thick, surface rough with 

 blunt warty elevations, apex slightly prolonged, monothalamor.g^ 

 Avali 1 mm. thick. They drop from the twigs in early May. Xo 

 investigation was possible and it is not known whether this is a bud 

 or acorn gall. The fly is so closely related to species from pip gails 

 on young acorns that it seems probable that this is an acorn gall. 

 After the galls drop an outer fleshy layer decays away, leaving a 

 stony shell with sharp longitudinal ridges. 



