ART. 10 GALL-INHABITING CYNIPID WASPS WELD 47 



AGAMIC GENERATION 



Female. — Similar in appearance to the female of the sexual gen- 

 eration except that freshly killed specimens from a breeding cage 

 kept out-of-doors for three winters in the humid climate of Wash- 

 ington are darker in color than the seven-year-old museum material 

 reared in the dry climate of California in July, only a short time 

 after the galls were collected. The ovipositor ratio, however, is 

 8.3 and wing 3.5. Length 2.6-3.7 mm. Average of 97 specimens, 

 2.98 mm. 



Host. — Quercus chrysolepis. 



Gall. — A mass of easily separated contiguous single cells lying on 

 one side of a nature acorn between the cotyledons and the acorn wall. 

 There is no visible external sign of infection, but very large acorns 

 in exposed situations on the tree seemed more liable to attack. The 

 individual galls are irregular in shape, slightly flattened, blunt- 

 ])ointed at the ends, 4-5 mm. long with exit hole 0.12 mm. in diameter. 



Biology. — There is no experimental proof that this is the alter- 

 nating generation, but the circumstantial evidence is strong. It 

 would be strange to find two series of adults with such unusually 

 marked wings emerging at different seasons from two strikingly 

 different galls on this host oak, which has almost a unique cynipid 

 fauna, unless they were so related. The longer ovipositor of the 

 sexual female seems adapted for piercing acorns and the shorter one 

 of the agamic female for laying eggs in small twigs. Because the 

 author considers these as one species no specific name is given to the 

 agamic form or type designated. The gall on the pin, the locality 

 label, and the field-note number 1577 will serve to identify the 

 agamic series before the author. 



Habitat. — The affected acorns were collected at Idyllwild, Calif., 

 on September 21, 1922, and the adults emerged at Washington, D. C, 

 March 12-21, 1925. Others will emerge in spring of 1926. 



PLAGIOTROCHUS SUBERI. new species 



Female. — Black, logs yellow. Head coriaceous, radiating ridges 

 about mouth, face pubescent; from above slightly broader than 

 tliorax, length to width as 21 :40, cheeks not broadened behind eyes; 

 from in front nearly circular, facial area slightly higher than broad, 

 malar space 0.3 eye, antenna filiform, li-segmented, lengths as (scape) 

 9 : 5 : 10 : 10 : 9 : 9 : 8 : 7 : 7 : 6 : 6 : 5 : 5 : 8, first two yellow, rest piceous. 

 Sides of pronotnm reticulate. Mesoscutum coriaceous, parapsidal 

 grooves deep, smooth, percurrent, broader behind, no median, a few 

 setigerous punctures along grooves. Scutellum with two large deep 

 smooth pits at base, disk coriaceous. Carinae on propodeura widely 

 diverging below and angled, enclosing an area in which there is a 



