150 APIDJE. 



somnis avails itself of the tube of a straw or reed, how is the insect 

 to pass the first knot, which would oppose its escape ? True know- 

 ledge is to be found in the careful investigation of nature. 



A bee is observed to alight on an upright post ; she commences 

 the formation of her tunnel, not by excavating downwards, as she 

 would in that case be incommoded with the dust and rubbish which 

 she removes ; no, she works upwards, and so avoids such inconveni- 

 ence. When she has proceeded to the length required she proceeds 

 in a horizontal direction to the outside of the post; and now her 

 operations are continued downwards ; she constructs a cell near the 

 bottom of the tube, a second and a third, and so on to the required 

 number. The larvae when full-fed have their heads turned up- 

 wards ; the bees which arrive at their perfect condition are the 

 males ; and it is these that are first anxious to escape ; they usually 

 do so several days before the females. This is the history of 

 every wood-boring bee that I have bred ; and I have reared broods 

 of nearly every species indigenous to this country. 



There is another species of this genus, whose habits are so different 

 from the rest that our admiration of the ingenuity of these bees is 

 greatly increased when we consider its curious details and reflect 

 upon the degree of care and foresight exhibited by the provident 

 parent ; this is the Osmia parietina, a bee only as yet found in the 

 northern parts of this country. This species selects the underside 

 of a slate or stone lying on the ground and having a hollow space 

 beneath ; to the underside of such stone the bee attaches little masses 

 of pollen and honey ; on each she deposits an egg, from which a 

 larva is hatched in a few days, which feeds upon the provision stored 

 for it by its provident parent. A stone of this kind was found in 

 1849 at Glen Almond, Perthshire, on the Grampians, at an eleva- 

 tion of 800 feet above the level of the sea, by Mr. J. Robertson, 

 who, on turning up the stone, observed a mass of cocoons of some 

 insect. Although not possessing much knowledge of entomology, 

 still he knew them to be the production of some insect ; he pre- 

 sented the stone to the British Museum, and it was placed in my 

 hands for observation. The size of the slab was 10 inches by 6, 

 and the number of cocoons attached to it 230 : when first dis- 

 covered, about one third of them were empty ; this was in the month 

 of November. In the beginning of the following March (1850) a 

 few males made their appearance, and shortly afterwards a few 

 females were developed ; they continued to come forth at intervals 

 until the end of June ; at this time there remained thirty-five unde- 

 veloped cocoons. On opening one or two in 1851 they proved to 

 contain living larvae. These cocoons were again carefully closed and 

 the whole left undisturbed until the month of April of the fol- 

 lowing year (1852), when, on examination, they were found still 

 to contain living larvae. At the end of May these changed to pupae, 

 which about the end of June became perfect insects, when both 

 sexes made their appearance. This, then, was the result : a portion 

 of eggs deposited in 1849 had been three years arriving at maturity; 

 or rather in all probability their development bad been retarded ; 



