158 Dr. Johnston on the Acarides of Berwickshire. 



Hybernation, I find, extends in general from October to March, 

 as few or no signs of being in an active or awakened state, such 

 as fgeces or the remains of insects upon the floor beneath, are to 

 be seen during this long winter-sleep. As soon, however, as 

 spring approaches, and the night-temperature rises to 46° or 48°, 

 I find the bat on such occasions in full activity; and as the 

 same temperature brings into active life a variety of nocturnal 

 Lepidoptera, which appear to be the favourite food of this Ple- 

 cotus, an abundant provision is ready for the support of this 

 animal upon awakening from its lethargic condition. From the 

 observations I have been able to make, it appears that the Ple- 

 cotus, upon the capture of a moth, returns immediately to his 

 retreat, and there devours the savoury morsel at his leisure, 

 shearing off the wings of the insect at the shoulder with his 

 sharp and cutting teeth. In this way the floor beneath the bat's 

 retreat, after a successful foray during the preceding evening, 

 exhibits the remains of the numerous victims that have fallen a 

 prey to his voracious appetite. To give some idea of the success 

 of our bat as a moth-catcher, the wings of the following species 

 were found upon the floor beneath his retreat on the morning of 

 the 19th of April last, after a warm and genial night, during 

 which he had revelled in all the luxury of a determined gour- 

 mand. As the wings were quite perfect, with scarce a scale 

 abraded from their surface, I was able to identify the species 

 without difficulty. They consisted of numerous wings of Or- 

 thosia stahilis, 0. gracilis, O. sparsa, Semiophora gothica, Glcea 

 satellitia, G. vaccinii, and a single pair of wings of Achatia pini- 

 perda, a rare moth, and a species I had never taken or seen be- 

 fore at Twizel. Since the date above mentioned, our bat seems 

 to have kept close at home, as I have not observed any additional 

 spoils beneath his domicile. In fact, the temperature has since 

 been sufficiently reduced to throw him again into the lethargic 

 state. 



The Acarides of Berwickshire specifically described. 

 By George Johnston, M.D. 



[Continued from p. 122.] 



35. Bdella dorsata. 



Bdella dorsata, Gervais in Walek. Ins. Apt. hi. 157. 



Body ovate, rostrate and pointed in front, of a yellowish or 

 pale orange colour with a large dark brown spot occupying the 

 greater portion of the back, sparingly hispid ; the venter pale 

 orange, unspotted. Rostrum tapered from a thickened base, 

 becoming rather suddenly narrower towards the apex, which is 



