194 



SCIENCE 



[N. S. Vol. XXXVIII. No. 971 



tlie trees within 20 miles south of Jackson. At 

 40 miles south of Jackson, the smaller trees 

 were so loaded with ice that they were bent to 

 the ground and many branches had been 

 broken off. Ten miles farther south, at 

 Eochester, N. H., there was no more ice on the 

 trees nor snow or ice on the ground. This 

 great difference in ice and snow covering was 

 the result of a difference in temperature of not 

 more than 5° (31° Jackson, 33°-40° Blue 

 Hill). 



In each of these three cases the daily weather 

 maps showed an area of high pressure 

 (" high ") directly north of a low pressure 

 area ("low"), both moving slowly eastward, 

 each more or less in the way of the other be- 

 cause of the prevailing tendency of a " high " 

 to move east-southeast and of a " low " to move 

 east-northeast in these parts of the United 

 States. These cyclones (" lows ") were thus 

 amply supplied with cold air in their northern 

 quarters. The ice storms occurred in the re- 

 gion where the normal warm southerly winds 

 on the east side of the cyclones overlapped the 

 cold north and northeast winds on the north- 

 ern side. 



Charles F. Brooks 



Blue Hill Meteorological Observatory 



a phlebotomus the practically certain car- 

 rier of verruga 

 Experiments on laboratory animals with 

 bloodsucking arthropods, looking to the solu- 

 tion of the problem of verruga transmission, 

 have been under way at Chosica, Peru, in 

 charge of the writer, since May 15, 1913. A 

 study of the bloodsuckers occurring in the 

 verruga zones has been going on for a longer 

 time. At first the vsrriter strongly inclined to 

 the theory "of tick or other acarid transmission, 

 but the trend of the investigation has been to 

 make such transmission seem very improbable 

 of late. No argasid ticks have been found to 

 occur commonly on mammals in the verruga 

 zones, and ixodid ticks will hardly explain the 

 night infection. The experiments in feeding, 

 biting and subcutaneous injection of animals 

 with the bloodsucking Gamasid mites of the 

 vizcacha, which seemed at first most promis- 



ing, have so far entirely failed of result. A 

 resurvey of the situation had therefore become- 

 necessary in order to start out on new lines. 



Culicids, Simulium, Tabanids, Stomoxys,^ 

 fleas, lice and bugs are all precluded either by 

 their extended occurrence, by their dependence- 

 on man, or by their day-biting proclivities. 

 The question of punkies and like small gnats- 

 remains. The writer's attention has recently 

 been drawn to the possibilities of Phlehotomus, 

 chiefly through the investigations recently- 

 published by Marett on the genus in the- 

 Maltese Islands. His results are most impres- 

 sive and suggestive in this regard. The habits 

 of the early stages and of the flies, as described 

 by Marett, fit so well into the conditions ob- 

 taining in the verruga zones that the conclu- 

 sion was irresistible that a Phlehotomus must 

 be the carrier of verruga. Hitherto there has- 

 been no record of the occurrence of Phlehoto- 

 mus in Peru, or anywhere in the Pacific coast 

 region of South America. 



Ceratopogon and other genera of Chirono- 

 midse with mouth-parts more or less adapted' 

 for bloodsucking occur at night both in and 

 out of the verruga zones. They were therefore- 

 contraindicated. Night collecting at Chosica,. 

 just below the limits of the verruga zone, has- 

 never disclosed Phlehotomus, and as these 

 gnats are never seen under ordinary circum- 

 stances in the daytime the writer determined' 

 to investigate the verruga zone by night in- 

 order to demonstate if possible the existence of 

 Phlehotomus therein. Accordingly he passed, 

 the night of June 25, 1913, at San Bartolome 

 in the verruga zone of the Eimac valley. The 

 result was that, besides Ceratopogon and other- 

 Chironomids, several specimens of Phlehoto- 

 mus were actually found. The natives call all- 

 nocturnal gnats titira, considering that most 

 of them bite, but certain of the more intelli- 

 gent distinguish the true titira as the Phle- 

 hotomus sp., stating that it has white wings. 



The true explanation of the oft-repeated' 

 facts that verruga is confined to deep and nar- 

 row canyons, with much vegetation, heat and" 

 little or no ventilation, evidently lies here. 

 The flies of Phlehotomus avoid wind, sun and* 

 full daylight. They appear only after sunset,. 



