20 HYMENOPTERA. 



of the Angular-winged Katydid, Microccntrus retincr- 

 vis Burm. (3, VI., 162). 



Cynipid^e {Gall-flies). 



Gall-flies resemble Chalcis-flies in appearance but 

 are usually plant parasites, living in abnormal vegeta- 

 ble growths, called galls. 



Note manner in which these galls are produced, and 

 compare them with galls produced by Plant-lice, 

 Bark-lice or Mites. (5, I., loi). 



The True Oak Apple, Quercus spongifica Osten 

 Sacken. 



The Mossy Rose Gall, RJwdites rosm Linn. (5 II 

 2I3). 



The Pithy Blackberry Gall, Diastrophtis nebulosus 

 0.sten Sacken. (5, II., 159). 



Tenthredinid^ {Saw-Jlies). 



The Saw-flies resemble the Lepidoptera in many 

 respects. The larvae are like caterpillars, usually feed- 

 ing on the leaves of plants. They may be distin- 

 guished, however, by having from twelve to sixteen 

 prolegs, while caterpillars never have more than ten 

 prolegs. The pupae usually transform in parchment- 

 like silken cocoons, in the ground or on the surface, 

 or on the limbs of trees. Adult with the three re- 

 gions of the body not so well marked as in the higher 

 Hymenoptera ; head broad ; thorax wide, closely re- 

 sembling that of the Lepidoptera ; abdomen sessile ; 

 ovipositor shaped like a saw ; hence the common 

 name of the family. (11, I., 31). 



Cimbcx Americana Leach. — The larvs feed on the 

 leaves of elm, birch, linden, and willow, (i, 215 • 2 

 518). 



