148 RESEARCHES IN HELMINTHOLOGV AND PARASITOLOGY. 



Besides the movements of progression induced by the cilia, the 

 animal wriggles in a sigmoid manner and even doubles on itself. 

 The contractile vesicles may contract more or less successively to 

 mere points, but apparently at no time entirely disappear, and they 

 may enlarge to double their usual size. The axial nucleus is at 

 first barely perceptible, but becomes very obvious as the animal 

 approaches dissolution. 



Incidently Prof. Leidy also stated that Aspidogaster conchicola, so 

 common in the pericardium of Anodonta and ilnio, he had also foiuid 

 in one instance in the oviduct of Paludina dedsa. 



[September. 1877. No. 444 See Bibliography.] 



(hi the Bed-bug and its Allies. — Prof. Leid}- remarked that it vva.** 

 commonly supposed that the swallow, pigeon, and bat were infested 

 with the bed-bug, and that those animals introduced the insect into 

 houses. Packard (Guide to Study of Insects, 551) observes that 

 the bed-bug " lives as a parasite on the domestic birds," and adds 

 that a gentleman informed him " that he has found a nest of swal- 

 lows on a court-house in Iowa swarming with bed-bugs."" West- 

 wood (Introd., ii, 475, note) says it is certain that bed-bugs " swarm 

 in the American timber employed in the construction of new houses. 

 " In the western part of our country," continued Prof. Leidy, " I 

 frequently heard that bed-bugs were to be found at any time be- 

 neath the bark of the cotton-wood and the pine. In these positions 

 I never found one, nor have I ever found the insect except in the 

 too familiar proximity of man. Recently, when in the West, while 

 watching some cliff swallows pa.ssing in and out of their retort- 

 shaped mud nests built under the eaves of a house, I was told that 

 these nests swarmed with bed-bugs, and that. usually people would 

 not allow the birds to build in such places, because they introduced 

 bed-bugs into the houses. Having collected a number of the bugs, 

 as well as others from the interior of the house, specimens of both 

 of which are submitted to the examination of the members, I found 

 that while the latter are true bed-bugs, Cimex leetii/arius, the former 

 are of a different species, the C. hirundinis. The bugs infesting the 

 bat and pigeon have likewise been recognized as a peculiar species, 

 with the name of C. pipistrelli and C. colionbariiisy Prof. Leidy 

 further noticed that the habit of the C. hinindinis was similar to 

 that of C. Icctidarius in the circumstance that the bugs during the 

 daytime would secrete themselves in crevices of the boards away 

 from the nests. After sunset he had observed the bugs leave their 

 hiding places and make their way to the nests. From these obser- 



