THE BED-BUG 295 



contribute in some way to their support ; but still it 

 must be borne in mind that, owing to the peculiar struc- 

 ture of their mouth organs, whatever be the nature of 

 the material from which they derive their food, only its 

 liquid portions can be partaken of. Anyhow, there 

 seems little doubt that human blood is not an absolute 

 necessary of life to this disgusting parasite, and perhaps 

 may be more correctly regarded as a luxury ; and it is 

 quite possible that before its association with mankind, 

 Cimex ledularius may have been a purely vegetable 

 feeder, subsisting on the sap of trees. Southall declares 

 that he fed the numerous families he kept on such food 

 as this, using chiefly deal for the purpose. Hard woods, 

 such as oak, walnut, and mahogany, or scented woods 

 such as cedar, they failed to extract any nutriment from, 

 and died if confined with these alone. 



Like all other insects, bugs, of course, breathe by 

 inhaling air, not at the mouth, but at certain openings 

 in other parts of the body, whence it is passed along 

 delicate tubes (tracheae) to all parts of the system. The 

 stigmata, or openings to the tracheae, are in the present 

 instance extremely small, and therefore not easy to trace. 

 They are situated on the under surface of the abdomen, 

 not far from the edge of the body. Perhaps the best 

 way to see them is to remove the chitinous band which 

 forms the boundary of any of the central abdominal 

 segments on the under side, and, after relieving it of 

 any adhering viscera, to examine it with the compound 

 microscope. A low power will be sufficient to show the 

 stigmata, one on each side, as minute roundish openings, 

 surrounded by a rim-like lip. From these pass the main 

 tracheal trunks, branches of which, like tiny threads of 

 silver, run hither and thither over the body. Their 

 silvery appearance is due to the air they contain. The 



