Aphididae 3 2 3 



APHIS MAIDI-RADICIS* 



THE complete life history of this corn-root aphis from the egg stage in 

 spring to the eggs in autumn has been obtained. The vivaria used for 

 the rearing and observation of the aphis consisted of 8- or io-dram vials, 

 each containing a ball of moist cotton in the bottom and plugged at the 

 top with a piece of cotton. In this cage a sprouting corn plant was 

 placed, a reserve supply of these food plants being constantly kept for use. 

 The first young and the last young of each generation were placed on corn 

 roots in separate vials. These vials were kept in closed boxes to exclude 

 light, thus giving conditions probably most favorable to the optimum 

 development of the aphis. As soon as the plant began to wilt it was 

 replaced by a fresh one, the aphids being transferred by means of a 

 camel's hair brush. 



During the life cycle of this aphid there appear five different forms, 

 namely: winged viviparous females, wingless viviparous females, ovip- 

 arous females, males, and eggs. Eggs were collected originally in the 

 nests of the common brown ant (Lasius niger L. var. americanus Emery) 

 in April. Taking the first young of the first young all through the series, 

 22 generations were obtained. 



M. E. D. 

 Reference 

 For the rearing of Aphis maidis see p. 397. 



REARING METHODS FOR APHIDIDAE 



F. M. Wadley, U. S. Bureau of Entomology and Plant Quarantine 



CONSIDERABLE work has been done in rearing the green bug 

 (Toxoptera graminum) and the apple-grain aphid (Rhopalosiphum 

 prunijoliae) ; some rearing has been done with Macrosiphum granarium, 

 the pea aphid, the melon aphid, the corn-leaf aphid, and several other 

 aphid species. Aphids have been reared almost entirely on growing 

 plants, though they will live for a time on cuttings in water. It seems 

 inadvisable to try rearing them on detached bits of food plant, as feed- 

 ing appears to be almost continuous. Many aphids seem to thrive under 

 a wide range of humidity and light conditions if on a favorable and 

 thriving food plant. They also develop under a fairly wide temperature 

 range, but it is difficult to carry some species through a hot summer. 

 In warm weather a shady, moist, well ventilated place should be sought 

 for cages for such species. Some species are quite susceptible to fungous 

 disease, and precautions must be taken against its entry. 



Cages must permit food plants to thrive, but otherwise have not 



* From an article in U. S. D. A. Tech. Ser. Xo. i2:Pt. 8, 1909, by J. J. Davis, Purdue 

 University. 



