24 
BULLETIN" 100, U. S. DEPARTMENT OF AGRICULTURE. 
her six legs and bends the hind part of the abdomen at a right angle 
to the rest of the body and then gives her abdomen a succession of 
jerks to get it into place. This performed to her satisfaction she 
remains motionless for 60 seconds while the egg is being extruded, and 
after depositing it walks off. The writer has never seen the eggs of 
this species placed in an open situation ; but always in some protected 
position in the bark. On August 28, 1912, four gravid females were 
dissected and were found to contain respectively 3, 4, 2, and 4 large 
eggs, and all had several smaller ones. Another had 8 large eggs in 
her ovaries and was greatly distended therefrom. The egg is bluntly 
oval, bright yellow when first laid, but changing in a day or two to 
black and obscurely shining. It measures 0.35 mm. in length and 
0.17 mm. in width, and is therefore considerably smaller than the 
egg of the European walnut plant-louse. 
The oviparous forms are described below. 
THE OVIPAROUS FEMALE, FULL GROWN (FIG. ll). 
General color pale greenish yellow or sometimes 
greenish white, the four apical segments of the 
abdomen at first colored like the rest of the body 
and later orange colored. Body rather narrow, 
not at all flattened, the sides nearly parallel and 
produced posteriorly into a conical tube. An- 
tennae a little over one-half the body in length, 
pale, with the apical third or fourth of joints III 
to VI dusky gray; joint II gray and armed with 
a capitate spine on its inner margin; joint III 
longest; joints IV and V subequal; joint VI 
shorter than its spur or filament. Legs very pale 
yellow, with a dark spot close to the apex of the 
anterior and posterior femora. (In many individ- 
uals these spots are absent.) Eyes pink. The 
arrangement of capitate spines is as follows: The head bears eight, the prothorax 
six, the mesothorax, metathorax, and abdominal segments 1 to 5, inclusive, 
four, and abdominal segments 6, 7, and 8 two; these spines appear as four lon- 
gitudinal rows. Cornicles greenish yellow, broader than long, hardly percep- 
tible, located on segment 6. Cauda concolorous with the body, globular, armed 
with four noncapitate spines, half as long as the hind tarsus. Genital plate protrud- 
ing beyond the cauda, pale, its margin beset with short noncapitate hairs. Beak 
pale, its extreme tip brownish, just exceeding the second pair of coxae. Measure- 
ments: Length of body, 1.68 mm.; width of body, 0.72 mm.; cauda, 0.038 mm.; 
antenna joint I, 0.04 mm.; joint II, 0.035 mm.; joint III, 0.300 mm.; joint IV, 
0.17 mm.; joint V, 0.17 mm.; joint VI, 0.100 mm.; filament, 0.12 mm. 
Fig. 
11. — Monellia caryas: Oviparous 
female. (Original.) 
Described from many specimens collected at San Jose, Cal. 
1912. 
during: 
