152 MEDICAL ZOOLOGY 



occupies a groove on the under side of the thorax. The first aud second 

 joints are cylindrical and equal in length; the last is longest and conical. 

 This apparatus is made up of three stiff, pointed setae. 



Habitat. The bedbug is common in old or carelessly kept houses. Prima- 

 rily it is an inhabitant of the woods, and may be seen under the bark on old 

 stumps. It insinuates itself in houses by various means, and finds lodgment 

 in cracks and recesses in all kinds of furniture. It studiously avoids light, 

 and is seldom seen from its hiding-place during the day. It will not live on 

 the bodies of persons, although it may take refuge in clothing and be thus 

 transported from place to place. The odor of the human body appears to 

 attract these insects, though other animals are^ilso subject to their attacks 

 (ba's and pigeons). Blood is not drawn by suction, however. After a 

 puncture is made, the insect receives the blood by capillary attraction aided 

 by the attending vertical motion of the several parts of the rostrum. Those 

 parts of the human body furnished with odiferous glands appear to be free 

 from their attacks. It is very doubtful whether, as has been said, they ever 

 introduce themselves into any of the cavities of the head, especially the 

 ear, with its guard of ceruminous material. The mark from the bite is 

 familiar to all. The irritation produced is doubtless due to the introduction 

 of some of the juices of the insect into the wound. 



The bug has its insect enemies. The Keduvius personatus seeks nearly 

 the same habitations with the bedbug, and when in search of prey covers 

 itself with dust and other material, so that it is impossible to recognize it. 

 It attacks the bedbug with its rostrum (it also is a Hemipterous insect) and 

 finds it an easy prey. Ants also seek and eagerly devour bedbugs. 



Many other Ilemipterous insects have the power of injuring man by the 

 prick of their rostrum. Among the most notable of these are the Prionotus 

 novenarius and several species of Notonecta and Nepa. 



Prionotus novcnarius may be found during the summer months on fences, 

 etc., in the country. It is generally about one inch long, and covered with a 

 very fine and dense cinereous pubescence. The head and neck are long and 

 cylindrical ; the thorax elevated into an acute serrated ridge, convex from 

 front to rear. The sides of the abdomen are rettexed, giving that part of 

 the body a concave appearance. The bug walks very slowly and with meas- 

 ured steps, and when caught by one not expert, inserts his rostrum into the 

 hand, causing a feeling of acute pain which may last for some hours, but 

 gradually passes away, leaving a feeling of numbness in the part. 



NOTONECTA (Boat-fly), Geoff. Hemiptera. Bcutellum distinct, rostrum 

 conical and articulate, tarsi of two joints each. The four anterior feet elbowed 

 with the tarsi cylindrical, simple and terminated by two hooks. Antennae 

 very short and but four-jointed. The thorax wider than long. The hemi- 

 elytra cover the abdomen above. The first two pair of legs are very short 

 and constructed on the plan of the land Hemiptera. The hind are, however, 

 very long and fimbriate, acting the purposes of oars, propelling the insect 

 witli. considerable rapidity under water. Body somewhat fusiform, obtuse in 



