The Lace Bugs 



Life History of the Hawthorn Lace Bug 



(Corythuca arcuata SayJ 



More than twenty years ago I saw most of the leaves of 

 a Hawthorn tree at Washington turning brown and rusty and 

 on examining them found the beautiful little Tingitid, shown at 

 Fig. 190, present in all stages of development. Projecting from 

 the leaf surface in groups of from ten to thirty along both sides 

 of the prominent leaf veins were certain minute brown funnel- 

 shaped objects which were found to be the eggs. Each egg is 

 laid on end and is covered with a brown sticky substance which 

 rapidly hardens and holds it to the leaf surface. This brown gum 

 adheres so strongly to the egg that it is impossible to remove 

 it without crushing the egg, and it is more copious near the base 

 so as to give the appearance of an actual insertion into the leaf 

 tissue. The top of the funnel has a porous cap which the in- 

 sect removes in emerging. The newly hatched bug grows 

 rather rapidly and casts it skin five times before becoming full 

 grown. While yet immature it is of the same dirty-brown color 



Fig. 191. Corythuca 

 arcuata : eggs and 



young. 

 (After Comstock.) 



Fig. 192. Piesma 



cinerea. 

 (After Riley.) 



as the substance covering the egg and but little darker than the 

 withering leaf. It is of a broad, flat, oval shape, and spines seem to 

 project from almost every portion of its body. It looks, under 

 the microscope, more like a lobe of prickly cactus than anything 

 else. A sticky honey dew is excreted by these bugs and their 

 cast-off skins adhere to the leaf and make it appear as if there 

 were many more insects present than is actually the case. 



During the winter the dead leaves under the trees were 

 found to contain living and healthy eggs, but the insect custo- 

 marily hibernates as a full-grown and winged bug. 



300 



