SCIENCE- G OS SIP. 



2 93 



chloroform. I apply its four anterior tarsi to the 

 interior of an air-pump receiver. By pressing 

 these slightly with the side of a needle, they adhere 

 firmly to the glass, and the insect remains sus- 

 pended in its interior. J now exhaust the air, and 

 the insect still remains suspended. It is necessary 

 to render the insect insensible, otherwise it volun- 

 tarily detaches itself" (''Trans. R. Micr. Soc," 



vol. v. 2C)7). The >tieky marks of the individual 

 hairs in the print of the foot of a Dyfiseus on a 

 glass slide afford additional proof of the presence 

 of an adhesive fluid, which Plateau found was 

 sufficiently powerful in a newly killed beetle to 

 sustain a weight more than thirteen times that of 

 the insect itself. 



(To In- continued.') 



BRITISH FRESHWATER MITES. 



By C. F. George, M.R.C.S. 



(Continued from page 231. J 



T 



Arrenurus gemvmis n.s. 



HIS pretty little mite belongs to Piersig's first 

 division of Arrenurus — that is to say that 

 the back part of the body is lengthened into a 

 cylindriform tail, narrowed at the base as in 

 A. eaudatus De Geer, which mite it somewhat 



there is a marking somewhat resembling two 

 lancet-shaped church windows placed side by side 

 (see fig. 1). Below this the tail is sloped off in an 

 irregular manner, forming three tiers, as shown in 

 Mr. Soar's drawing (fig. 2). These markings are 

 best seen in the living mite, for shortly after 

 being kept in preservative solution the blue colour 



Fm. 1. 



Fig. 3. 



$> y 



T^A 



Km. t. Fm. 5. 



Figs. 1 to 11. Arrenurus geminus 



resembles. Its general colour is blue, with a 

 triangular white mark in the centre, the apex 

 directed backwards ; the eyes are crimson, and the 

 fourth internode of the last pair of legs is fur- 

 nished with a spur, as in many other male 

 ArrenUri. At about the lower third of the tail 



disappears, and the whole mite becomes a nearly 



uniform warm brown, the eyes turn black, and the 

 markings are not so easy to differentiate. 



When I examined one of these mites I observed 

 two transparent glass-like conical projections at 

 the end of the tail (see fig. 3). These gradually 



