BLOOD-SUCKING BUGS AND DISEASE 479 



At present very little is known regarding the habits and life histories 

 of the Rhynchota, and there is, therefore, a wide field for research in this 

 direction. With regard to their affinities to other insects no two ento- 

 mologists are agreed, so that mere statements of the views which are held 

 would be of little practical use. 



Bugs are of considerable interest to the parasitologist, as many of the 

 commonest species are infected with various kinds of proto/oal parasites, 

 of which the flagellates of the genera Herpetomonas and Crithidia are the 

 best known. One of these parasites, H. lygaei, Patton, from Lygaeus 

 pandarus, is indistinguishable in its pre and post-flagellate stages from 

 the parasite of Kala Azar as seen in man. According to Lafont the 

 flagellate parasitic in Conorhinus rubrofasciatus in Mauritius, if inoculated 

 intraperitoneally into mice, becomes transformed into a trypanosome in 

 the blood. 



The blood-sucking bugs are confined to the families Reduviidae and 

 Cimicidae, and only about a dozen species are known to have this habit, 

 the bed bugs, Cimex lectularius and C, rotimdatus, being the most familiar. 

 The family Polyctenidae contains a few very aberrant bugs which are 

 parasitic on bats ; very little is known regarding them. 



Of all the blood-sucking insects associated with man, the bed bug is 

 unquestionably the commonest ; although its sanguivorous habits are well 



known, yet from the point of view of disease it is the 



, j r 11 u T .LU Blood-sucking Bugs in 



least understood of all human pests. In reviewing the re | at j on to Disease 



600 odd papers dealing with Cimex lectularius, Girault 

 points out that those who have studied it from the entomological stand- 

 point exhibit an entire lack of knowledge of the medical literature 

 connected with it ; the medical man, on the other hand who, discusses 

 this insect from the disease standpoint, shows an equal deficiency in his 

 knowledge of the entomological literature relating to it, and more par- 

 ticularly of that dealing with its structure. 



In 1887 Metchnikoff, in a paper on Relapsing Fever, referred 

 to the r6le of the bed bug, Cimex lectularius, in disease ; this is the 

 first time that this insect is definitely suspected. Since then numerous 

 attempts have been made to associate it with the transmission of 

 various kinds of pathogenic bacteria, particularly the bacillus of plague. 

 Verjbitski, however, is the only observer who has brought forward 

 any substantial experimental proof that lectularius can transmit Bacillus 

 pestis. 



Goodhue and others have endeavoured to demonstrate that lectularius 

 may also carry the bacillus of leprosy; the evidence which has been 



