found in Virginia and Pennsylvania. 239 



The insect does not kill the spiders which it collects in 

 this manner, but leaves enough of life in them to prevent 

 them from putrefaction or from drying up. In all the cells 

 that I opened, I found the spiders in a state of languor, 

 which admitted of their moving their limbs without chan- 

 ging their places. We can conceive nothing more painful 

 than their situation : they are huddled together for the pur- 

 pose of being; devoured piecemeal by the young wasps, for 

 whose food they are destined. 



Each of the cellules of the Pennsylvanian wasp, being in- 

 tended to contain a certain number of spiders, is separately- 

 constructed ; but the sphex cccrulea, which builds a long 

 tube, gathers as many spiders as it thinks necessary ; and, 

 after having laid an egg, encloses it along with the spiders by 

 means of a transverse division of clay. It lays another egg 

 in the following cellule, which it fills and shuts up in the 

 same manner, and so on with four or five cellules in the 

 same tube. 



The egg is not long of hatching after being closed up ; 

 but the author was not able to ascertain the time required 

 for the formation of the young wasp. There are drawings 

 coloured after nature published with the memoir, giving sec- 

 tions of the cells of these wasps, and showing the different 

 periods of the transformation of the insects. 



As I always found an unequal number of spiders in va- 

 rious cells, but apparently proportioned to their capacity, 

 I opened a range of the cells of the Pennsylvanian wasp ; 

 and having weighed separately the contents of each, I ob- 

 tained the following results : 



Grains. 



In the first cellule the spiders weighed - 7-j. 



Jn the second, there were 1 7 spiders and an empty 



skin; the worm weighed \ grain, and the spiders 6-J 

 The third contained 19 very small spiders and some 



emptv skins ; the whole weighed - - 5?. 



The worm weighed - - - - J + 



The fourth contained only carcasses of spiders, the 



worm was weak and feeble. I presume that it had 



too little nourishment, or that it was sick ; it 



Ked, - t - - - 3j- 



The 



