Further reports (no. 5) on flies as carriers of infection.

Date:
1912
Catalogue details

Licence: In copyright

Credit: Further reports (no. 5) on flies as carriers of infection. Source: Wellcome Collection.

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    “ complained of a bad throat ” for about a week. Further details were unfortunately not forthcoming. As bearing upon this case, however, it is perhaps worth mentioning that at Leipzig, in Germany, in the spring of the year 1830, a living larva of Thereva nohilitata is stated to have been vomited by a youth who had been unwell for a fortnight, but made an immediate recovery when the intruder was expelled. Syrplius or Lasiopticus spp. incert. (Hover-Flies). Everyone must be familiar with the flower-haunting, yellow- banded or yellow-spotted Hover-Flies of the genera mentioned, which are common in gardens and open spaces in woods, and derive their popular name from the habit—shared by other members of their family—of remaining poised apparently motion- less in the air for many seconds at a time, supported on rapidly beating wings. The larvae of these flies are soft-bodied, greenish, greyish, or whitish grubs, flattened on the ventral surface, and with the dorsal integument marked by numerous transverse wrinkles. They are good friends to garden-lovers, since they feed on the juices of Aphides, which they destroy in large numbers. From the normal mode of life of Hover-Fly larvae, it would seem in the highest degree improbable that they should ever be associated with Myiasis, and their presence in the human body must be regarded as purely accidental. Yet on two occasions within the last ten or eleven years a single Syrphid larva, nine or ten millimetres in length, and apparently belonging to one or other of the genera under consideration, has been submitted to the author by different medical men, accompanied by the state- ment that the creature had been discharged per rectum by a patient; while in a third instance a similar larva was removed from the external auditory meatus. In the latter case, which occurred in June, 1909, the patient (a messenger-boy in a Govern- ment office) suffered from deafness and pain in the ear, and the symptoms were stated to have commenced two days before the larva was removed. Eristalis tenax, L. (The Drone-Fly). Eristalis teriax, the popular name of which is due to the well- known resemblance of the insect to the male of the Hive-Bee, is found in many parts of the world, and is common everywhere in the British Islands, especially in autumn, when it is frequently to be met with on ivy flowers. It is a large dusky brown or blackish brown fly (often Avith conspicuous orange markings on the sides of the abdomen in the male), measuring rather more than half an inch in length, and distinguishable from other species liable to be confused with it by the fact that each of the eyes bears a double vertical ridge of dark brown hairs, which, when the insect is closely examined Horn above, stand out conspicuously from the general hairy covering of the eyes. Like the other species of its genus, the Drone-Fly breeds as a rule in water charged ^ The numbers refer to the list of “ References ” at the end of this paper.