47 



several cases where confined upon the plants, although sometimes 

 inserting the beak and feeding, they died with the ovaries filled 

 with young. The migration of winged lice from the ground was ob- 

 served at the same time in neighboring fields where, on the 27th of 

 July, many of these winged lice, chiefly dead, were found on the 

 blades. A careful search of the roots, made at the same time, 

 showed that the root form was now rare in situations in which it 

 had done most injury in the spring. 



Root lice were obsei'ved on the enclosed corn until the latter part 

 of August, but were not again uncovered until October 7, the ant& 

 in the meantime being constantly observed running in and out. On 

 the morning of October 7, the infested plants were dug up carefully 

 and carried in doors for careful examination, and upon one of the 

 roots which had several times during the season been found to 

 support plant lice was found a small colony of oviparous females, 

 the only egg-laying examples of the species which up to the time 

 had been seen. They bear a close resemblance to the more 

 common viviparous female of the root form, as the following de- 

 scription will show : — 



The Ociparous Female Aphis maidis [root form]. — General color, 

 dull green; body covered with a glaucous bloom. Above, head dusky, 

 prothorax chiefly dusky, the three succeeding segments each with a 

 median transverse dusky blotch, all the segments behind the pro- 

 thorax with a marginal and submarginal series of dusky specks on 

 each side. Below, head and prothorax dusky, two dark spots out- 

 side the coxa of the middle leg, a dusky line before the coxa of the 

 hind leg, abdominal segments with two series of dusky specks on 

 each side and a pair of dark spots before the cauda. Antennae, 

 two basal articles, third and fourth at tips, and fifth and sixth 

 chiefly, dusky. Eye brownish red. Rostrum dusky. Anterior and 

 middle legs with the coxfe, femora except at bases, tibia3 at tips, 

 and tarsi except bases, dusky. Posterior leg, excepting the extreme 

 base of the femur, black. Cornicles black. Cauda with black bor- 

 der. Body stout, its greatest width at about the middle. Outline 

 of the front seen from above incurved medially. Antenna with 

 first and second articles equal in length, the first stoutest ; third 

 article about equal in length to the fourth and fifth together, the 

 latter nearly equal in length and similar in form ; basal part of 

 sixth article shorter than the distal part, about equal to the fifth 

 in length. Cornicles short, not at all swollen at the middle. The 

 limbs and cauda have the usual slight pubescence of members of 

 the genus Aphis. 



Length of body 2.27 mm. 



Width of body* 1.20 mm. 



Antenna 80 mm. 



Cornicle .20 mm. 



Perfectly developed eggs taken from the ovaries are oval in shape, 

 pale yellow in color, and measure about .78 mm. 



In addition to the discovery of the oviparous female of the root 

 form another interesting fact in the life history was observed dur- 

 ing the season. A careful lookout was kept for any tendency of the 

 plant lice, both within and outside the enclosed frame, to breed on 



