] 992 Insects. 



Curious Habit of a Dipterous Insect. — Whilst watching the many dipterous insects 

 that visit the flowers of the golden-rod, I noticed a very curious act of piracy. A 

 large fly (whose name I have not been able to ascertain), with enlarged thighs, well 

 suited for leaping, would settle on the plant, and remain for some time on the look- 

 out. Suddenly it would seize a smaller fly engaged in gathering honey, and detain 

 it for a short space, without doing it any apparent injury. On watching more nar- 

 rowly, I found that the predatory fly compelled its victim to disgorge its store of ho- 

 ney, and thus obtained a kind of food which it was either unable or unwilling to 

 gather from the blossoms. — J. W. Slater. 



Medeterus regalis. — I took several specimens of this rare fly on the 9th of August, 

 towards evening, in Cockburnspath, Tower dean, Berwickshire. It frequents in com- 

 panies the faces of the rocks by the side of the burn, especially those in the shade, 

 which the rivulet bedews with its spray as it works forward its troublous passage. It 

 is usually to be observed squatting, but when alarmed it gets up on its long crane- 

 like legs, prepared to start off to a new retreat. A few mornings after, I noticed seve- 

 ral others on the banks of the river Eye, in the same county. — James Hardy ; Pen- 

 manshiel, by Cockburnspath, Berwickshire, October 5, 1847. 



Aqueous Vapour expelled from Bee-hives. — " There is one circumstance connected 

 with the economy of the bee-hive which does not appear to have engaged the atten- 

 tion of naturalists. It is the transpiration of vapour from the interior of the hive, at 

 certain seasons, during the act of ventilation. Every bee-keeper must have noticed 

 that at the latter part of the summer there is often a deposit of blackish carbonaceous 

 matter on the footstool of straw hives, which is extended a few inches from the en- 

 trance-hole. This deposit is accumulated there in the course of a few months. 

 When it first attracted my attention, I supposed that it was occasioned by the bees 

 alighting at that spot, and accidentally shattering some of their loads of pollen ; or 

 that, perhaps, it might be rejected excrementitious matter ; but I afterwards satisfied 

 myself that it does not arise from either of these causes. The pollen conveyed by the 

 bee is rarely or ever shattered in its transit, while the bees are always particularly 

 careful to romove obnoxious materials from the interior of their dwelling or its imme- 

 diate vicinity. Other circumstances have since led me to believe that it results from 

 the accumulation of small quantities of wax that had adhered to the feet of the bees 

 that have just left the combs and are passing outwards, and that its dark appearance 

 may perhaps be due to the same cause as that which discolours the combs in the in- 

 terior, and changes them, in the course of a few months, from a delicate yellow to a 

 dark brown, and even to a blackish hue. 



" When a hive is examined very early in the morning, at the end of summer, after 

 a fine cool night, we usually observe at the entrance-hole a stream of moisture passing 

 from it, sometimes in drops. This is more or less abundant at different periods, ac- 

 cording to the temperature of the preceding day, the activity of the bees, and the 

 coolness of the night. There seems reason to believe that this fluid results in part 

 from the respiration of the bees, and the extraneous transpiration from their bodies, 

 generated during the night in the form of vapour, which is condensed and deposited 

 as it comes into contact with the cold night air during the ventilation of the hive. 

 It has already been stated by Huber, that the vitiated air of the hive is removed by 

 the fanning of the bees, and that by this process a double current of air is established. 

 The respired air is removed by the one, while fresh air enters by the other. My own 

 observations have fully satisfied me of the correctness of these statements, and I have 



