6

dissected on the fifth day. My reason for drawing attention to the number of
times the bugs were fed will be seen later.

   Donovan has attempted to confirm my observations on the development of
the parasite in Cimex rotundatus. On three occasions he fed bugs on suitable
cases, but states that he found no developmental changes in the parasites
ingested, even after a week or ten days. He gives no precise details of these
experiments. Being dissatisfied with his attempts to infect Cimex rotundatus
he has searched for some other blood-sucking insect of local distribution, and
one which is not so ubiquitous as the bed bug. He has succeeded in finding
Conorrhinus rubrofasciatus de Geer, which he considers to be the most likely
transmitter of the disease. He notes that both male and female conorrhini can
be found which contain either digested or fresh mammalian blood in their
midguts, and that both the adults and nymphs will readily suck up human
blood. He records a flagellate of the genus Crithidia (C. conorrhini, Donovan)
from the alimentary tract of the adult insect. He has fed this insect on suit-
able cases of Kala Azar, but has been unable to find any of the developmental
forms of the parasite, and is now inclined to abandon the idea that it is the
natural carrier. In connection with this insect I may point out that I have
fed on myself the adult insect and several of the nymphal instars, and have
found that the bite is most irritating. The actual puncture made by its
proboscis is felt as a sharp sting, and about 12 hours later a large erythematous
patch about the size of a shilling appears at the site of the bite; it remains in
an inflamed and irritable condition for about a fortnight and then fades away,
and a small nodule the size of a No. 6 shot persists for about one month. I
therefore feel certain that were this bug a common blood-sucker in the Indian
houses in George Town, it could hardly escape detection; further, the marked
symptoms resulting from its bite could not possibly escape observation. In 1906
when I visited the houses of people suffering from Kala Azar, on enquiring
what insects were in the habit of biting them, I never even heard of this
Conorrhinus ; it is a large coloured insect, and if it were a regular blood-sucker
it would surely be well known. Recently I have endeavoured through several
medical friends to obtain some information regarding its distribution in George
Town, and as a result I have obtained a single specimen. On further enquiry I
found that it never bites people, but is attracted by a light and will thus enter a
house. I have however now had the opportunity of carrying out some feeding
experiments with this bug, and these observations are described further on.
This concludes the summary of all the experimental work which has been
carried out in India with blood-sucking insects, and I will now give a critical
review of the recent work on the closely allied form of Kala Azar of the Mediter-
ranean littoral.