ECONOMIC ZOOLOGY ENTOMOLOGY. 659 



may bear 50, 60, or even TO young, and each of these in turn may bear as many 

 young, and so on throughout the season. The winter is usually passed in the 

 egg stage. 



At least 2 species of primary parasites, Xystus hrassicw and Aphidius 

 (Diceretus) piceus, are abundant in New York State. Other insects, reared 

 from the bodies of aphids on cabbage leaves, were Aswplies rufipes, supix)sed to 

 be a hyperparasite, and Pacliyneuron micans. Two species of lady beetles, 

 namely, AdaUa hipunctata and Hippodamm convergens, were very abundant in 

 1910 and did effective work in destroying the aphids. The larvae of at least 

 4 species of Syrphus flies, namely, SphwropJboria cylindrica, AUograpta obliqua, 

 SyrpJins americana, and B. rihcsU, were seen feeding on the aphis in the State. 



Methods of control include the destruction of cabbage leaves and stumps, 

 dipping of seed-bed plants or fumigation of seed beds with tobacco paper, and 

 the spraying of plants in the field. Seed-bed plants were dipped in a home- 

 made fish-oil soap made in the following proportions: Caustic soda 1^ lbs., 

 water 1* qts., and fish oil 5* lbs. A 1 : 8 solution of this soap is said to have 

 killed every aphid hit. In experiments with Leggett's Anchor Brand of whale- 

 oil soap, 1 : 8 solutions gave equally good results, but weaker solutions of 1 : 10 

 and 1 : 15 were inferior to like solutions of the fish-oil soap. But few aphids 

 were killed when plants were dipped in Blackleaf 1 : 64. 



"A series of plants dipped in solutions of lime-sulphur, 32.5° B. in the pro- 

 portions of 1 : 40 and 1 : 30, were quite badly burned in every case and only a 

 small percentage of aphids was killed. The tendency of the lime-sulphur to run 

 off the leaves without apparently touching the aphids was almost as marked 

 as in the case of the tobacco extract. In . . . laboratory experiments in which 

 individual plants well infested with lice were sprayed with solutions of lime- 

 sulphur at the rate of 1 : 20, 1 : 15, and 1 : 10 of watei", respectively, the plants 

 were injured in every case and but 55 to 65 per cent of the aphids was killed." 



In tests made of Nico-fume, 1 paper was used to every 25 sq. ft. of surface, a 

 smoke-proof muslin attached to a skeleton frame 1 ft. high being used as a 

 cover. The aphids on plants fumigated in this way for 30 minutes were killed 

 and the plants not injured. 



It was found that the homemade soap solutions did not kill the immature 

 stages of the parasites when protected by the dried skins of the dead aphids. 



The authors estimate that cabbages in the field can be sprayed with a power 

 sprayer at a cost not to exceed 75 cts. per acre. It was found in field experi- 

 ments that the cost with a knapsack sprayer was a fraction over $2.15 per acre, 

 including labor and material when the fish-oil soap was used and could be 

 purchased at 3^ cts. per pound. 



A list of the more important articles on this aphis is appended. 



The cabbage aphis, Aphis brassicae, G. W. Herrick {Jour. Econ. Ent., 4 

 {1911), No. 2, pp. 219-22Jt). — The data here presented are included in the article 

 noted above. 



White files injurious to citrus in Florida, A. W. Morbill and E. A. Back 

 (U. 8. Dept. Agr., Bur. Ent. Bui. 92, pp. 109, pis. XO, figs. i9).— This bulletin 

 presents the principal results of studies of the life history, seasonal history, 

 habits, food-plant relationships, etc., of the citrus white fly {Aleyrodes citri) 

 and the cloudy-winged white fly (A. nubifera). 



A list is given of 12 species and one subspecies of Aleyrodidse known to 

 breed upon citrus, together with their distribution and food-plant records. Of 

 these, A. citri, A. giffardi, A. Jioivardi, and A. niiMfera are known to be orange 

 pests or capable of becoming orange pests. A. floridensis, A. mori, A. mori 

 arizonensis, and Paraleyrodes persece apparently are not likely to cause injury 

 to citrus, while the 5 remaining are doubtful in this respect. 



