1919] ECONOMIC ZOOLOGY — ENTOMOLOGY. 161 



The role of the field rat in the epidemiology of plague, L. On en (Meded. 

 Burgerl. Gencesk. Di< >ist Nedcrland. hidif, No. 8 [1917), pp. 1-81; uhx. in Jour. 

 Anur. Med. Assoc, 71 (1918), No. 5. p. 418).— Examinations of 2,111 field rats 

 (Mus niltus ilianlii) resulted in the collection of l.ON. - ! adult tleas, of winch 

 576 were Loemopsylla cltiopis and 507 were Pulix iiltultr. The author's investi- 

 gations Indicate that the field rat gets L. cheopiS from the house rat, hut that 

 this flea dies Off out-doors when Inclement weather arrives. P. nhnlir inf. 

 the Qeld rat. throughout the year. While the held rat is susceptible to plague, 

 the author does not ascribe any Importance to it in the spread of plague from 

 village to village. 



On the duration of infectiousness of the Indian rat flea (Loemopsylla 

 cheopis), L. Otten (Meded. Burgerl. Qeneesk. Dienst Nederland. Indie, No. 6 

 (1911), pp. 120-126; abs. in Jour. Amrr. Med. Assoc., 11 (1918), No. 5, p. 415).— 

 In connection with the investigations above noted the author found that this rat 

 flea may transmit plague for a period as long as 43 days. 



Aristonetta, a good genus, H. C. Oberholseb (Proc. Biol. Soc. Wash., 31 

 (1918), p. 98). 



Hierofalco rusticolus candicans in North Dakota, H. C. Oberhoi.ser (Proc. 

 in,, j. 8oo. Wash., 31 (1918), p. 91). 



Olor columbianus on the Potomac River, H. C. Oberhoi.ser (Proc. Biol. 

 Soe. Wash., 31 (1918), p. 91). 



Spizella monticola, the correct name for the North American tree sparrow, 

 II. ('. Oberholseb {Proc. Biol. Soc. Wash., 31 (1918). p. 98). 



Squatarola squatarola cynosurce near Washington, D. C, H. C. Oberhoi.ser 

 (Proc. Biol. Soc. Wash., 31 (1918), p. 91). 



Ninth annual report of the State entomologist, C. P. Gillette and G. M. 

 List (Off. State Ent. Colo. Circ. 26 (1918), pp. 52, fig. 1).— Included in this re- 

 port are brief notes on the insect pests that have caused the most damage to 

 orchards in Colorado and have received the most attention, namely, the San 

 Jose" scale, Putnam scale, Howard scale, codling moth, fruit-tree leaf roller 

 (Archips argyrospila), and pear-leaf blister mite; and on shade-tree pests, in- 

 cluding the European elm scale, black locust borer (Prionoxystus robiniw), and 

 cottony maple scale. 



The first infestation of the alfalfa weevil in Colorado was discovered early 

 in July, 1917, near Paonla, in the upper part of the North Fork Valley, Delta 

 County. Infestations were found as far east as Bowie, 5 miles east of Paonia, 

 but no weevils could be found west of the town. 



Tests of insecticides are reported upon by G. M. List (pp. 36-45). Blackleaf 

 40 used against the apple aphis, the most serious insect of young apple orchards 

 in Colorado, was found to destroy all the aphids at a strength of 1 : 700 and 

 but a few survived at strengths up to 1 : 1,500. The addition of soap was 

 found to be of considerable benefit in aiding the liquid to penetrate the curled 

 leaves and wet lice that were not in exposed places. The mealy plum louse 

 (Hyalopterus ammdinis), which often does considerable damage to plum and 

 prune trees in the State, was not destroyed by blackleaf 40 to which fish-oil 

 soap had been added when used at a strength of 1: S00. 



Injury to foliage by nicotin sulphate sprays led to experiments which demon- 

 strated that a small amount of injury on the tips of leaves of all plants will 

 result from the application of spray at strengths of 1 : 50, both with and without 

 soap. The injury was not severe, being more marked on the plum and rose, 

 and only on the rose did it cause any spotting of the leaves. The dilution of 

 1 part to 100 parts of water, both with and without soap, gave a very slight 

 amount of burning on all plants except the apple. The dilution of 1 : 150, with- 



