1835.] Scientific Intelligence. 461 



the covering, and joins the rest in the labours of the nest. As soon 

 as the neuters are hatched the care of feeding the larvae devolves 

 upon them. The males appear to employ themselves in cleaning and 

 preparing the cells for successive broods. 



Mr. Bigge has never found, in any single instance, a male larva 

 in the cells appropriated to females. He has repeatedly found male 

 grubs in the upper layers, which are devoted to neuters, but never 

 the contrary. The beautiful arrangement by which the layers in 

 the nest are attached to each other so as to allow room for the wasps 

 to walk between them deserves attention. In the ground nests the 

 supports or braces are round, like small columns, and dispersed at 

 irregular distances. The upper end is spread along' the edges of 

 three cells so as to divide the pressure, and yet allow room for the 

 grubs to work their way out when they are come to maturity. In 

 the tree nest, instead of pillar like braces, thin slips of the paper of 

 which the whole nest is composed but made stiffer for this purpose, 

 are continued along the edges of a number of cells, so as not to 

 interfere with the inmates, and are finally fixed to the layer below. 



The author has never seen a nest of either species, in which he 

 did not observe after 9 o'clock in the summer months, a sentinel 

 watching the entrance to the hive. He has sometimes thought, that 

 he could discern a second sentinel, behind the first one. A lantern 

 held near the sentinel does not disturb him, but on touching the 

 ground near him, he instantly disappears for a few seconds, and the 

 inhabitants sally out immediately. Several wasps pass the night in 

 summer on the outside of the tree nest, but the sentinel is notwith- 

 standing always at his post. 



The ground nest has two apertures, one for entry and the other 

 for exit. The tree nest has usually only one, but in large colonies 

 there are two, at each of which a sentinel is stationed. It is curious, 

 that if we stop up a wasp's nest, the returning wasp will not sting 

 the aggressor, while those which escape from the inside will attack 

 him instantly. The grub of a species of volucella is found in the 

 nests of wasps. An ichneumon as large as the wasp itself, with 

 a black head, yellow abdomen with a dark streak down the back, 

 black legs and under wings, and dusky upper wings has been observed 

 by Mr. Denison, and another (Anomalon Vesparum) by Mr. Wood. 

 Mr. Twiss mentioned a peculiar kind of wasp's nest which he had 

 observed on the Cactus in Sicily. The author suggested the query, 

 whether it was not the Epipone Fidulans, sometimes found also in 

 England. 



Dr. Kidd read a paper on a species of manna produced in the neigh- 

 bourhood of Mount Sinai. 



It is a gum which exudes from a species of tamarisk, through 

 minute punctures in the bark made by insects. It drops upon the 

 ground in a liquid state, but congeals by the cold of the night. It 

 is eaten by the natives, and has a sweet taste. 



Though denominated by Niebuhr, "manna Israelitarum," the 

 author argues that it must not be confounded with the manna m en- 

 tioned in Scripture, since the quantity produced at the present day 

 would be utterly inadequate to the supply of so numerous an assembly. 



