BULLETIN 100, IT. S. DEPARTMENT OF AGRICULTURE. 



Fig. 3. — Chromaphis juglandicola: Larva of 

 stem-mother after second molt. (Orig- 

 inal.) 



After the second molt the spines on the dorsum of the body disap~ 

 pear. (See fig. 3.) 



The pupal and imaginal stages of the stem-mother show no appar- 

 ent difference in respect to size, color, or structure from those of the 



later viviparous generations, and thus 

 one description of these forms will suf- 

 fice for all the winged viviparous gen- 

 erations. 



THE PUPA OP THE WINGED VIVIPAROUS 

 FEMALE (FIG. 4). 



General color pale lemon-yellow. Eyes red, 

 fully formed. Antennae reaching a little be- 

 yond the base of the wing-pads, pale, joint III 

 the longest, joints IV and V subequal. Ocelli 

 present. Anterior margin of the head bearing 

 six capitate spines. Thoracic segments pale 

 yellow. Wing-pads pale yellow, closely ap- 

 pressed to the sides of the body. Legs pale 

 yellow, with the dark knee spot on the hind 

 femora only; tarsi dusky. Abdomen oval, pale 

 lemon-yellow, with a varying number of dark 

 spots on the dorsum, which spots are always present on segment 5 but often lacking on 

 the other segments. Head, thorax, and abdomen furnished with lateral rows of capi- 

 tate hairs which stand on small pale tubercles. Cornicles small, as wide as long, 

 slightly constricted in the middle, situated on the sixth abdominal segment. Cauda 

 short, about as long as the cornicles, bluntly rounded at the apex. Cornicles and 

 cauda concolorous with the body. Beak short, pale, stout, reaching to the first pair of 

 coxae. The pupa has the legs relatively a little shorter than those of the adult and is 

 thus more closely appressed to the leaf surface . The 

 body is quite flat. Measurements: Length of body, 

 1.87 mm. (average); width, 0.85 mm. (average max- 

 imum);, antenna, joint I, 0.050 mm.; joint II, 

 0.042 mm.; joint III, 0.183 mm.; joint IV, 0.081 

 mm.; joint V, 0.076 mm.; joint VI, 0.065 mm.; 

 filament, 0.034 mm. Cornicles, 0.04 mm. 



The stem-mothers pass through the 

 pupal molt about one week before the final 

 molt takes place, and after the latter they 

 acquire their full development as winged 

 adults. In the latter generations the 

 pupal instar occupies from three to six 

 days. 



THE WINGED VIVIPAROUS FEMALE (FIG. 5). 



General color pale lemon-yellow; many individ- 

 uals are darker yellow, yellowish-brown, or salmon- 

 pink. Antenna; on very small frontal tubercles, about one-half the length 

 of the body, yellow, with the inner lateral margins of the first two joints dusky; 

 articulations of joints III to VI and the whole filament dusky to black. Eyes red. 

 Ocelli present. Prothorax yellow. Thoracic lobes and scutellum light brown, some- 

 times greenish-yellow, pale yellow in newly-molted individuals. Wings of medium 



Fig. 4. — Chromaphis juylandicola: 

 Pupa of winged viviparous fe- 

 male. (Original.) 



