1915] Biology of Juniper Berry Insects 169 
THE JUNIPER BERRY GENIOCERUS. 
Geniocerus juniperi Crawford 
This species has been proved to differ from all the other 
known members of this parasitic group in that it is plant-feeding 
in habit. They are, by far, the most abundant, there being 
often as many as eight or ten larve in a single berry. The 
young larve were observed from the time tley were visible 
until they were full-grown, and found to live in tight-fitting 
burrows (Fig. 5 b, Pl. XVIII), that gradually become larger as 
the insect feeds and grows: This fact alone is sufficient to 
establish its plant-feeding habits. It is very inactive and a 
moderate feeder, as compared with the Eurytoma larve. There 
is but one generation a year, and the winter is passed in the 
larval stage. 
“Female.*—Length about 1.5 mm. Lemon-yellow, with dark brown 
markings on the rear of the head, front of pronotum, and small brown 
spot on each lateral angle of pronotum, one on front of axille, suture 
between mesoscutum and scutellum; propodeum medially; spot on 
each side of abdominal segments and the apical margins of segments 
more or less suffused with brownish; scape yellow with a brown spot 
above, rest of antennz brownish; joints of funicle elongate; seen under 
high power the antenne show three ring joints; head and thorax finely 
sericeous; median furrow of mesoscutum rather indistinct, median pair 
of furrows on scutellum about half as far apart as length of scutellum; 
propodeum with median carina hardly as long as the metanotum; 
submarginal vein with about four bristles; legs yellow with the apical 
joint of tarsi brown; ventor along median line somewhat brownish; 
sheaths of ovipositor apically distinctly brown. 
Paratypes vary in having more brown, the mesoscutum medially 
with a large brown spot in front; vertex, parapsidal areas anteriorly, 
sides of propodeum with brown spots; the abdomen with the bands 
more pronounced.”’ 
As the males are very much fewer in number, I did not 
succeed in locating one in my rearings until January 2, 1915. 
Male——Length 1.2.mm.; abdomen 0.5 mm. Color lemon-yellow, 
but the whole dorsal surface much darker than in the female. These 
darkened areas are more pronounced on the rear of the head, propodeum, 
furrows of scutellum, and abdomen. The latter has the dorsum brown, 
excepting for the anterior and posterior extremities, while the apical 
margins of the segments are darker. The whole ventral aspect lemon- 
yellow, except for a small area on the prothorax. The antennz are 
* Female to be described by J. C. Crawford, Proc. Ent. Soc., Wash. Male 
described by author. 
