Brumpt showed that the development could take place in three species; bed-bugs (_Cimex lectularius_, _C. hemipterus_) and in the tick _Ornithodoros moubata_. The evolution proceeds in the first two species of bed-bugs as rapidly as in Conorhinus, or even more rapidly, but they remain infective for a much shorter time and hence Brumpt considers that they play a much less important rôle in the spread of the disease. _Conorhinus megistus_, like related forms in our Southern States, very commonly frequents houses and attacks man with avidity. Chagas states that the bites are painless and do not leave any traces. They are usually inflicted on the lips, or the cheeks and thus the buccal mucosa of a sleeper may be soiled by the dejections of the insect and the bite serving as a port of entry of the virus, remain unnoticed. The possibility of some of our North American Reduviidæ playing a similar rôle in the transmission of disease should not be overlooked. LEISHMANIOSES AND INSECTS--Closely related to the trypanosomes is a group of intracellular parasites which have recently been grouped by Ross under the genus _Leishmania_. Five species are known to affect man. Three of these produce local skin infestations, but two of them, _Leishmania donovani_ and _L. infantum_, produce serious and often fatal systemic diseases. The first of these, that produced by _L. donovani_, is an exceedingly virulent disease common in certain regions of India and China. It is commonly known as "Kala-azar," or "dum-dum" fever, and more technically as tropical leishmaniasis. Patton (1907) believes that the parasite is transmitted by the bed-bug _Cimex hemipterus_, and has described a developmental cycle similar to that which can be found in artificial cultures. On the other hand, Donovan was unable to confirm Patton's work and believes that the true intermediate host is a Reduviid bug, _Conorhinus rubrofasciatus_. _Leishmania infantum_ is the cause of the so-called infantile splenic leishmaniasis, occurring in northern Africa, Spain, Portugal, Italy, and possibly other parts of Europe. The parasite occurs habitually in the dog and is only accidentally transferred to children. Alvares and da Silva, in Portugal (according to Brumpt, 1913) have found that the excrement of a flea from a diseased dog contains flagellates, and they suggest that the infection may be transmitted by the accidental inoculation of this excrement by means of the proboscis of the flea, as has been thought to occur in the case of the plague. To this Brumpt objects that they and other workers who thought to trace the development of _Leishmania infantum_ were apparently misled by the presence of a harmless _Herpetomonas_ which infests dog fleas in all countries, even where the leishmaniasis is unknown.