420 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



feed and consequently fitted to ovenvinter and produce the eggs for the 

 first generation of the next year. Control work pursued as the adults of 

 the fall peak are decreasing and directed against the larvae invariably 

 reduces to the minimum the numbers of overwintering females. 



The practicability of these measures is not limited to a tlieoretical 

 examination of the charts but has been demonstrated in actual field 

 practice in California. In the fall of 1919, the writer had charge of an 

 anti-malarial campaign at Anderson in Northern California, where 

 prelim.inary work was undertaken in August. B}- October first, as far as 

 repeated field inspections could determine, control was absolute. The 

 work was continued on permanent ditches until December first during 

 which time no larvae were observ^ed. Work was then discontinued by our 

 project, the responsibilities being assuir.ed by local authorities. On the 

 following spring at the tim.eof the migratory em.ergence flight in surround- 

 ing areas, Anderson was comparatively free, a few adults drifting in from 

 unprotected areas with the result that the individuals of the first brood 

 even if uncontrolled would have been of little sanitary importance. 



In the spring of 1921, the abrupt and overwhelming migratory emer- 

 gence flight so incensed an already educated municipal population in the 

 northern part of California that public clamor demanded im.mediate 

 action on the part of the health authorities w.ho responded by draining 

 and oiling all breeding places in the m.unicipality, hitherto a notorious 

 malaria center. The first brood never em.erged, and by midsummer 

 mosquito control operations were discontinued as no larvae could be 

 found within the area. On previous years when work was started at a 

 later date the entire appropriation for m.osquito control was invariably 

 exhausted before the season drew to a close and mosquito control was 

 problem.atical. This year, however, with work starting at a ver}-- early 

 date m.osquito control was absolute by midsumm.er and fully one-half 

 the appropriation which was the same as on previous years, remained in 

 the city t^easur^^ 



As A. punctipennis Say and A. pseiidopiincipennis Theobald did not 

 breed in the immediate vicinity of the collection point, the discussion is 

 limited to A. occidentalis D. & K. Of these two species above mentioned, 

 little is known concerning their hibernation in California. No records 

 of adult capture during the winter months are at hand nor have their 

 larvae been taken during this period'-. Control measures directed 

 against A. occidentalis as outlined above would control these species as 

 well should they be shown to winter over as larvae. 



^Mitzmain has observed overwintering females of A. punctipennis in Mississippi. 



