'63 



for new feeding-grounds affording greater shade or security, but 

 neither sex of T. trijunctus is affected in this way. The spraying of 

 the blooms with an arsenical solution to poison the adults that visit 

 them for their nectar has been suggested as a possible means of 

 controlling these troublesome flies, which however will probably 

 continue to be detiimental to the welfare of hve-stock until artificial 

 drainage of the Everglades is undertaken. 



New records of species collected at Paradise Key include 

 T. americamis. Forster, T. rufus, P. de B., T. turbidus, Wied., 

 T. luguhris, Macq., T. atratus, F., T. melanocerus, Wied., T. lineola,F., 

 T. costalis, Wied., T.flavus, Macq., D.ferrugatus, F., Chrysops plangenSj 

 Wied., and C.Jlavidus, Wied. 



Marchand (W.). First Account of a Thermotropism in Anopheles 

 punctipennis, with Bionomic Observations. — Psyche, Boston, Mass., 

 XXV, no. 6, December 1918, pp. 130-135, 2 figs. 



A study of Anopheline mosquitos in the region of Princeton, New 

 Jersey, yielded only two species, namely, Anopheles quadrimaculatus 

 and A. punct/ipennis. It is not definitely laiown to what extent the 

 latter species is harmful, but it is doubtful whether it is a regular 

 carrier of malaria in the northern States, where it occurs as far 

 north as Boston. In rearing A. jnmctipennis in captivity it was 

 found that certain green unicellular surface algae, placed in clear 

 water, formed the most satisfactory food for that species. It has 

 also been stated that in the Sudan microscopic fresh-water algae 

 form the principal food of Anopheles ; this might prove an important 

 fact in control, as the mosquitos might be kept in check by methods 

 aiming at destruction of the algae. 



Observations upon the biting instincts of A. punctipennis show that 

 they are determined mainly by thermotropism. It has previously 

 been recorded that females of Stegomyia alhopicta {scutellaris) were 

 attracted by hot air radiating from a test-tube filled with hot water. 

 Shed blood and perspiration were not, however, more attractive to 

 the females of this species or of Culex fatigans than water. Females 

 of A. punctipennis were kept in lamp chimneys and were fed 

 on apple jelly spread out on a glass plate and covered with filter 

 paper. It was found that the apple jelly was more readily taken if 

 heated. In order to ascertain whether the odour of the jelly or the 

 heat coming from it was the chief attraction, the j elly was removed 

 from the glass plate which was then heated to a degree above the 

 human body temperature, and replaced under fresh filter paper. The 

 mosquitos were attracted in the same way as if food had been 

 present, all attacking the surface of the filter paper and bending their 

 proboscis in repeated efforts to pierce the surface of the plate. 

 Males shoAved the same tropism as females, but much less strongly. 

 As soon as the glass plate had cooled off, the mosquitos became 

 indifferent. Upon re-heating, the same effect was observed both with 

 the same and with other individuals. The author has since tried to 

 confirm these facts by observations on other species of mosquitos, 

 but as yet only hibernating females of Aedes sylvestris have been 

 used, and these did not show any trace of the thermotropic reaction 

 observed in A. punctipennis. They consistently refused to bite, 

 though various foods other than blood were readily accepted. 



