180 



captured at points in the vicinity within a period of four weeks. The 

 rats would appear to have an instinctive desire to wander, as any 

 " homing " instinct must be excluded in view of the circumstances 

 attending their capture, liberation and recapture. In addition to 

 obtaining data on rodent emigration, the experiment furnished an 

 index to the efficiency of the trapping ; 103 of the 179 rats in the 

 first series were recaptured during the following month and of the 

 113 in the second series, 60 were recaptured in 26 days. All the rat.s 

 used in the experiments had been examined and found free from 

 infection. 



Fbicks (L. D.). Rocky Mountain Spotted Fever found present in 

 South-eastern Montana. — Public Health Reports,Washington, D.C ., 

 XXX, no. 23, 4th June 1915, pp. 1694-1695. 



On 25th April 1915, cases of Eocky Mountain spotted fever were 

 reported from south-eastern Montana, outside the supposed area of 

 distribution of Dermacentor andersoni and D. modestus. All the cases- 

 seen were of the mild type observed in Wyoming and all were recover- 

 ing. An investigation of grazing conditions showed that south-eastern 

 Montana was formerly a horse and cattle country and that subsequently 

 sheep superseded them to a considerable extent. About five years 

 ago, dry farming was first undertaken in this district. The farmers 

 occupied the water-holes and settled along the small water-courses, 

 thus in turn driving the sheep away from the settlements. Each 

 farmer brought a few horses and milk cows and thus established a 

 breeding place for ticks in his immediate vicinity. Tick infestation 

 has greatly increased during the last few years; all the specimens 

 collected by the author were D. andersoni. 



Cooper (W. F.) & Walling (W. A. B.). The Effect of Various 

 Chemicals on Blow-fly. — Ann. App.Biol, Cambridge Univ. Press, ii, 

 nos. 2 and 3, July 1915, pp. 166-182. 



The experiments described in this paper were made with the object 

 of determining the insecticidal effect of various chemicals the bulk of 

 which have never been actually employed as insecticides. Most of 

 them are articles of commerce and the others, if found effective, could 

 be produced on a commercial scale. The larvae of CalUphora vomitoria 

 were used for the experiments, but some of the results were interfered 

 with by the attacks of an unidentified Chalcid. Maggots were at first 

 bred on horse-flesh, but, the supply proving inadequate, they were 

 purchased of dealers in anglers' requisites. It was after the use of 

 the purchased maggots that the Chalcids appeared and caused a 

 mortality which in some cases exceeded that amongst the chemically 

 treated larvae. The method of experiment was as follows : slabs of 

 horse-flesh about 1 lb. in weight were placed in shallow cardboard boxes 

 and the exposed surface was dusted over with the reagent, suitably 

 diluted with precipitated chalk. The boxes were then exposed to the 

 flies and daily note taken of any " blowing " ; controls of untreated 

 meat were similarly exposed. Forty-three different chemicals were 

 tried in this way, and the results are set out in a table showing the 

 strength of the chemical used and the number of days before the flesh 



