374 BEDBUGS AND THEIR ALLIES 



vary juice has already been poured, draws blood up through a 

 tube made by the piercing organs, through a thickened " bottle 

 neck " ring to the oesophagus and then into the relatively enor- 

 mous stomach. The muscles for dilating the pharj^nx in order 

 to make a suction pump out of it occupy the greater part of the 

 head. According to Cragg, who has worked 

 on the alimentary tract and digestive proc- 

 ess of bedbugs, there are about 70 pulsa- 

 ^* tions of the pharynx per minute in young 

 bugs, in which this can be observed through 



Fig. 166. Diagram the body wall. Bugs seldom cling to the 

 S%ot?bo'^ngback «ki^ While sucking, preferring to remain 

 of proboscis. (After on the clothing. Since a fresh meal appar- 



^^^^'y-^ ently acts as a stimulus for emptjdng the 



contents of the rectum, the adherence to the clothing is a fortunate 

 circumstance, inasmuch as it precludes to some extent the danger 

 of bedbugs infecting their wounds with excrement, as do ticks. 



In the course of ten or 15 minutes a full meal is obtained and 

 the bug, no longer flat but round and distended with blood, re- 

 treats to his hiding place, having first deposited a bit of excrement. 

 According to Cragg, in the case of C. hemipterus (rotundatus), a 

 single meal, much of which is temporarily stored in the stomach 

 which acts as a food reservoir as well as a digestive organ, is not 

 fully assimilated for at least a week, although the bug is ready to 

 feed again in a day or two, thus having parts of several meals in 

 the stomach at once. This is quite a different condition from 

 that found in most blood-sucking insects, where a meal is com- 

 pletely digested before another is sought. Observations made 

 by several authors on C. lectularius do not indicate that this 

 species has similar habits. As in other bugs, the digestive juices 

 change the absorbed blood into a dense black mass, described 

 by Murray as almost like lamp-black. 



The bite of the bedbug seldom produces pain or swelling unless 

 rubbed or scratched, a fact which indicates either that the saliva 

 is not irritating or that it does not ordinarily reach the wound 

 before sucking begins. In some people, however, a stinging, hard, 

 white swelHng is produced. 



Under normal conditions the common bedbug, C. lectularius, 

 has only rarely been found feeding on anything but human blood. 

 The bugs which infest the nests of swallows and other birds are 



