Studies in relation to malaria / by Samuel T. Darling.

  • Samuel Taylor Darling
Date:
1910
Catalogue details

Licence: Public Domain Mark

Credit: Studies in relation to malaria / by Samuel T. Darling. Source: Wellcome Collection.

    29/46 page 25
    =e mo STUDIES IN RELATION TO MALARIA. 25 DURATION OF LIFE OF MALES AND FEMALES IN CAPTIVITY. Male specimens of A. pseudopunctipennis which have been kept in breeding jars with females, and supplied with raisins, dates, and water, have lived for eighteen days. Male specimens of A. albimanus have lived twelve and one-half days. On the other hand, a virgin specimen of Stegomyia calopus has lived for one hundred and ten days. When virgin anophelines have been given one or two blood meals, two or three days after emerging, they have lived as long as sixteen days. This is in rather striking contrast with Stegomyia calopus, which, under similar conditions, lives months to the anophelines’ weeks. Several specimens of S. calopus virgins still under observation have lived for several weeks, and have oviposited as late as sixty days after emerging, though never in contact with males. MUSICAL NOTE OF MOSQUITOES. — XG CAR AMevato@ Los The characteristic musical note of anophelines is camseet=bsy the vibration of the proboscis, as the following observation indicates: A specimen of A. malefactor was badly wet and sprawled; upon placing her upon a piece of filter paper and touching or approaching her proboscis the latter vibrated visibly, and emitted the characteristic high-pitched note; the wings were at rest, being stuck to the paper. This was verified again and again. Later I picked up a slightly water- sprawled infected mosquito for dissection and held it over a few drops of chloroform; both wings were seen to vibrate rapidly, as in flight, but noiselessly; while holding the mosquito by the last abdominal segment, and touching one wing at its tip the opposite wing would immediately stop vibrating. Upon releasing the wing, both would vibrate noiselessly, as before. The noise of the mosquito is tee; then, to the vibration of its proboscis, and the wing vibration is dependently - and automatically coordinated. aor RELATIVE VALUE OF DIFFERENT FOODS FOR ANOPHELINES. After trial with bananas, I found that raisins and dates, with water furnished the best food for anophelines in confinement. A greater number of males and females may be kept alive during the few days after emergence if fed with fresh banana, raisins, or dates; but females fed on this diet daily would not bite with alacrity. Mosquitoes fed daily or on alternate days on human blood made better dissections after the digestion and evacuation of their meal than those fed on bananas. The former would be fairly free from yeast and bacteria, and the mid gut and appendages would not disintegrate so rapidly after death. If the mosquitoes were fed alternately on bananas and blood, they would frequently die with an undigested, hard mass of blood in the mid gut, which must have been either impossible to digest or evacuate. The best method of feeding infected mosquitoes would seem to be to feed two or three times on a patient favorable for infec- tion and subsequently with raisins, dates, and water. Then, too, the acid contents of the mid gut, after banana feeding, with its fermenta- tion, may interfere with the infection of mosquitoes by malaria. In experiments Nos. 20 to 28 a patient having at times 67 crescents per 100 leucocytes in his peripheral blood was bitten by four varieties of
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