24 



BULLETIN 100, U. S. DEPARTMENT OF AGBICULTURE. 



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, PULL 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. 



Described from many specimens collected at San Jose, Cal., during 

 1912. 



Fig. 11. — Monellia caryx: Oviparous 

 female. (Original.) 



