Published online by Cambridge University Press: 31 May 2012
The discovery that most plant-bugs emit, when disturbed, a kind of highly penetrant and nauseous odour is not of recent origin. However, it has since then been thought that the presence of such odoriferous scents exists probably in direct adaptation to the needs and habits of their possessors. The frequent occurrence of such an odour consequently stirred the curiosity of the earlier workers to determine the exact source of this scent. No documentary account of such an attempt was, however, available until 1833 when Leon Dufour published an account of the anatomy and physiology of Hemiptera. It was thus revealed by him that the real source of the odour was actually a gland, on each side, in the ventral part of the metathorax, opening to the exterior by means of very small apertures, lying one on each side of the metasternum between the second and third pairs of legs. He worked on many hemipterous bugs, and in Cimex lectularius mentions, for the first time, in addition to the glands, a median reservoir which may be oval or round and membranous in appearance. Dufour's publication gave further impetus to the following workers, and thereafter we find persistent attempts having heen made from time to time to work out the morphology of the glands. It may be mentioned that in view of the later discoveries of the chemical nature and the odour of the secretion in various insects, the use of the term Scent-apparatus would be more precise than stink or repugnatorial scent-apparatus, employed by most of the workers up to this day, for the secretion is not repugnant in many insects; in some it has even an agreeable odour like that of ripe bananas or ether. Brindley (1930) also seems to prefer the use of the term Scent-apparatus.