548 HYMENOPTERA. 



spot on the back. It is three twentieths of an inch long, 

 and its wings expand three tenths of an inch. It is the 

 Diplolepis, or more properly Cynips oneratus of my Cata- 

 logue. 



Galls of the size and color of grapes are found on the 

 leaves of some oaks. Each one contains a grub, which 

 finishes its transformations in June. The winged insect is 

 my Cynips nubilipennis, or cloudy- winged Cynips, so named 

 from the smoky cloud on the tips of its wings. Excepting 

 in this respect, it closely resembles the dark-colored variety 

 of Cynips oneratus, and very little exceeds it in size. 



One of our smallest gall-flies may be called Cynips semi- 

 nator, or the sower. She lays a great number of eggs in a 

 ring-like cluster around the small twigs of the white oak, 

 and her punctures are followed by the growth of a rough 

 or shaggy reddish gall, as large sometimes as a walnut. 

 When this is ripe, it is like brittle sponge in texture, and 

 contains numerous little seed-like bodies, adhering by one 

 end around the sides of the central twig. These seeming 

 seeds have a thin and tough hull, of a yellowish- white color ; 

 they are egg-shaped, pointed at one end, and are nearly 

 one eighth of an inch long. The gall-insects live singly, 

 and undergo their transformations, within these seeds ; after 

 which, in order to come out, they gnaw a small hole in the 

 hull, and then easily work their way through the spongy 

 ball wherein they are lodged. They are less than one tenth 

 of an inch long, are almost black, or of the color of pitch, 

 highly polished, especially on the abdomen, and their mouth, 

 antenna?, and legs are cinnamon-colored. 



It has been observed that no tree in Europe yields so 

 many different kinds of galls as the oak. Those which I 

 have described are not all that are found on oaks in this 

 country, and they seem to be sufficiently distinct from the 

 galls of European oaks. 



Round, prickly galls, of a reddish color, and rather larger 

 than a pea, may often be seen on rose-bushes. Eac-h of 



