141 



pupal stages, the following hymenopteroiis parasites were reared : 

 the Braconid, Phanerotoma recitrvariae, Cushrnan ; the Ichneumons, 

 Diadegma sp., and Itoplectis sp. ; an undetermined Pteromalid ; 

 an Encyrtid, Eupelmus sp. ; an Eurytomid, Eurytoma sp., and a 

 Chalcid, Dihrachys sp. 



Two experiments, which are fully described, show that the lesser 

 tud-moth can be controlled by thoroughly spraying the trees in the 

 dormant state with lime-sulphur solution at 32° Baume used at the 

 rate of 1 part to 8 parts of water. Lower testing material should be 

 used at increased strengths. The spraying should be done just before 

 the bud swells, or preferably when the buds are swelling. This treat- 

 ment is especially to be recommended, as it involves no extra appli- 

 cation where it is necessary to spray during the dormant season for 

 other insects, such as San Jose scale, oyster-shell scale, scurfy scale, 

 bhster mite, and the peach leaf -curl. In cases where it is not expedient 

 to use the Hme-sulphur solution, two early applications of arsenate of 

 lead at the rate of 2 pounds to 50 U.S. (42 Impl.) gallons of water should 

 be made. This should be applied first, when the buds are swelhng, 

 and again when the cluster-buds open. This latter application coin- 

 cides with the first apple-scab treatment. In case of a bad infes- 

 tation, it woidd be advisable to make another application of arsenate 

 of lead when the buds are half open or bursting. It should be borne 

 in mind that thorough control of this insect, by use of an arsenical, 

 necessitates keeping the buds covered with poison as much as possible 

 from the time they begin to swell until they are open. 



Davidson (W. M.). Walnut Aphides in California. — V.S. Bur. Agric, 

 Washington, D.C., Bull. no. 100, 31st August 1914, 48 pp., 18 figs., 

 4 pis. [Received 16th February 1915.] 



The species of Aphididae known to occur on walnut in California 

 are ChromajMs juglandicola, Kalt. (the European walnut aphis), 

 Monellia caryae, Monell (the American walnut aphis), Monellia 

 caryella, Fitch (the little hickory aphis), and Monellia californica, 

 Essig. The last species is the subject of brief mention only, while 

 the others are fully described in all their stages and forms. C jug- 

 landicola alone infests walnuts of commercial value in California, but 

 latterly M. caryae and M. caryella have been found to be pests on native 

 walnuts, much used for stock on which to graft the European or Persian 

 nut. C. juglandicola probably occurs wherever the European walnut 

 is grown. It is found sporadically on the underside of the leaves and 

 on the young fruit of the European walnut, and its cultivated forms 

 and hybrids. It appears on the upper surface of the leaf only at times 

 of severe infestation. Badly infested nuts mature when only half 

 grown and the attacks on the tree materially reduce its vitality. The 

 sweet excretion of this aphid attracts large numbers of ants, Formica 

 subsericea, Say, being the most abundant. 



Monellia caryae, Monell, was first collected in Missouri in 1879. 

 It occurs on the leaves of the walnut, hickory, and pecan, and has been 

 reported from Illinois, Nebraska, Oregon and Michigan. It doubtless 

 occurs in America wherever its food-plants grow. The character and 

 extent of its injury is similar to that of C juglandicola. Formica 

 obscuriventris, Mayr, is a very common attendant ant, and F. subsericea 



