Miscellaneous Intelligence. 329 



the anal extremity of the libellula, to the extent sometimes of several 

 inches; at the same time the force with which the column is ejected propels 

 the insect in the opposite direction, by virtue of the resistance with which it 

 meets. Hence it appears that it is by means of its respiratory system that 

 the creature walks — a strange and anomalous combination of functions in 

 one organ. 



" If the insect be taken out of the water, held with its head downwards, 

 and a few drops of that fluid poured on its tail, that which was a mere point 

 will immediately open and display a cavity ; at the same time the body of 

 the insect, which was before flaf, will fce observed to be enlarged and inflated, 

 and if held up to the light, semitransparent : moreover, something solid will 

 appear to be displaced by the water, and driven towards the head. This 

 solid mass will shortly descend, obscure the transparency of the lower por- 

 tion of the body of the insect, lessen its diameter, and, when it does so, a jet 

 of water will issue from the vent. It is clear, then, that the abdomen of the 

 libellula is a syringe, the piston of which being drawn up, of course the pres- 

 sure of the fluid fills up the vacuum, and, when pushed down, expels the 

 water. 



" After the voracious creature has Iain in ambuscade devouring the larvae of 

 the gnat and other aquatic insects, till its appointed hour of change, it leaves its 

 natal element for the shore, to undergo its last metamorphosis : for this purpose 

 it usually fastens itself to some friendly plant, and begins the important process 

 which is to convert an aquatic animal into an inhabitant of the air. 



"Any person who should at this period choose to seize a number of them, and, 

 taking them into his chamber, fix them to a bit of tapestry, would be rewarded 

 for his trouble by witnessing the conversion of an aquatic into an aerial insect 



u It may easily be seen by the eyes of the nymph whether it is about to change 

 its form; for, instead of remaining tarnished and opaque, they suddenly become 

 transparent and brilliant. This change is owing to the visual organ of the perfect 

 insect, which is amazingly lustrous, shining through the mask of the nymph. If 

 the eye of the nymph be removed, that of the perfect insect may be seen beneath. 

 As soon as the nymph has fixed itself to any object by means of its claws, the 

 first sign of the commencing metamorphosis is a rent in the upper skin, extend- 

 ing along the corslet to the head. When it approaches this latter part, another 

 rent, perpendicular to the first, runs across the face from eye to eye. These 

 rents are brought about by a power which the insect possesses of inflating its 

 body and head. This last organ, ultimately destined to become fixed and solid, 

 is at this period capable of contraction and dilation, like a membrane. 



" The head and corslet being exposed, the legs are drawn out from their nym- 

 phine cases. At this period every part of the insect is soft. After having pro- 

 truded itself thus far, it hangs with its head downwards, and remains motionless, 

 80 as to lead the observer to believe that the efforts which it had hitherto made 

 had exhausted its strength, and that it had thus perished in the act of being born. 

 However, it remains in this position just so long as to permit its body and limbs 

 to be hardened by the air, and then reverses it, forming an arch; this enables 

 the insect to draw out its tail from tbe mask." 



Stature of Men in the Department of France.— In the second number of 

 a periodical quarterly work lately commenced under the title of Annahw 

 de P Hygiene pubUque, there is a curious Memoir by Dr. Villenne, on i he 

 Stature of Man in France, and the consequences to be deduced from it for 

 Natural History and Legislation. Among the curious facts which Dr. V. 

 has demonstrated, is one, that the human stature is more elevated, catcris 

 paribus, in rich countries than in poorer, and in cities than in the country. 

 During the existence of the French empire and the conscription, several 

 millions of men were measured, and from their measurements it results 

 that the richest, departments always supplied the tallest conscripts, and 

 presented the smallest number discharged on account of disease. The poo- 

 pie of Paris are taller than the inhabitants <>f the other part of the depart- 

 ment of the .Seine, and those of Lyons than the inhabitants of the arrond' 

 ment of Villefranche. Besides the influence of wealth, Dr. V. recogn 

 certain local influences ; marshy countries produce a stunted as well as a 

 miserable race: mountaineers are not tall generally, except in countries 

 where the people are in easy tircumstani 



Tt 



