232 ; October, 



others have a very wide range over the ocean. Thus, R Wullerstorffi 

 appears to extend over the entire Atlantic Ocean between the parallels 

 of 43° N. and 20° S. latitude, sporadic examples occasionally reaching 

 the shores of North Carolina (Uhler, I.e.), and is also widely distri- 

 buted in the Pacific Ocean, over the northern half of which R. sericeus 

 is also extensively spread. The former species may even be said to 

 extend to European waters, as a specimen in the Oxford Museum is 

 recorded as from Cape Einisterre. It is even not impossible that stray 

 specimens may reach, the south-western shores of these Islands by 

 means of the Grulf Stream, like Janthina, Physalia, Velella, and other 

 organisms of warmer oceanic regions. The Chusan Islands, where I 

 saw these insects in greater abundance than anywhere else, lie well 

 outside the tropics, being intersected by the 30th parallel of N. 

 latitude, and they have a winter of considerable severity, even colder 

 than our own ; their summer, however, from June to the end of Sep- 

 tember, is exceedingly hot, and the temperature of the surface-water 

 of the sea surrounding them rises above 80° for a large part of 

 this time. 



I have, in conclusion, to thank Mr. C. O. Waterhouse, of the 

 Natural History Museum (where most of my specimens of Halohates 

 are deposited), for kind assistance in identifying the species. 



23, Eanelagh Road, Sheerness : 

 August 30th, 1893. 



ON THE HABITS OF MESOVjELIA FURCATA, MULS. & RET. 



BY EDWARD A. BUTLER, B.A., B.Sc, F.E.S. 



This species of Rydrometridce has so seldom occurred in this 

 country, and so little seems to be known of its habits, that the results 

 of a few observations on a colony I have recently met wdth may be of 

 some interest to Hemipterists. The colony in question I found last 

 August on a pond in an orchard in the hamlet of Fifield, between 

 Maidenhead and Windsor. The pond was a long narrow one, about 

 120 ft. by 30 ; on its banks were growdug Alisma, Polygonum, Lycopus, 

 Mentlin, Bidens, &c., and in the water was abundance of Potamoyeton 

 natans, together with Polygonum, Chara, and some other pond- weeds. 

 Mesovelia w^as to be found on the leaves of the Potamogeton, but, in 

 consequence of the greenish colour and extreme slenderness of the 

 insects, it was exceedingly difficult to see them from the banks, and, 

 in fact, I could never be quite certain that I distinguished them, and 

 the numerous small I>i]ptera which were also running about over the 



