BIORHIZA RENUM. 101 
by W. H. Hammonp, of a transverse section through 
a bud with ova in situ, and of three ova alone, deserve 
careful examination. 
Biorhiza renum, Hartig. 
(Plate XXXIV.) 
Trigonaspis renum, Mayr; Trigonaspis megaptera, Cameron : 
Biorhiza renum, Giraud, Adler, Miiller, Mayr, Fitch. 
English name of gall.—‘‘ The Kidney Gall.” 
Position of gall.—On the under-surface of leaf. 
Manner of growth. — Glabrous, glossy, gregarious, con- 
glomerated. : 
Colours.—Yellowish-green, green, red, purple, dark brown. 
Average dimensions of a mature specimen.—Reniform 
type: Height, 1] mm.; length, 2mm.; breadth, 1 mm. 
May be sought during the months of September and October ; 
occasionally November. 
Growth is complete by the end of October. 
The typical condition of the gall is unilocular and unilarval. 
The larva pupates in the gall. The imago emerges during 
May and June. 
Parasites, Nos. 2, 10, 59, 74,105. Inquilines, Nos. 134, 138, 
1389, 140, 148, 145. 
Alternate sexual generation: Trigonaspis crustalis, Hartig. 
The ovoid and spherical forms, and solitary speci- 
mens of this gall are apt to be confused with those of 
Neuroterus ostreus by anybody beginning to collect oak 
galls. Many examples are very much alike. Several 
features, however, serve to distinguish the species. B. 
renum is rarely spotted, and then not to the same 
extent as N. ostreus, the latter though is sometimes 
without spots. B. enum never has the little valve- 
like membraneous pieces of leaf tissue at its base, nor 
the minute papille on its surface as does N. ostreus, 
while the latter never occurs in parallel rows. 
The shape and mode of growth of this gall are both 
distinctive and attractive. The shape is that indicated 
by its specific appellation, viz. like a kidney. Occa- 
sionally specimens develop into an ovoid and a spherical 
