322 OHIO EXPERIMENT STATION: BULLETIN 332 



uses in boring holes into the solid wood for oviposition. The general 

 body color is brown with distinct yellow markings on the abdomen. 

 (See Plate LXX, Fig. 3.) 



Life history. The adults of the pigeon tremex emerge from 

 the trunk of the host through holes almost as large as a lead pencil. 

 Eggs are deposited in the manner previously described. The result- 

 ing larvae eat their way into the wood. Since they ultimately 

 become 2 inches or more in length they are capable of much injury 

 to the host. It is not known whether more than 1 year is required 

 to complete the life cycle. 



Food plants. Maple is the favorite food plant, but in addition 

 to this host, apple, pear, beech, oak, sycamore and probably others 

 are subject to attack. 



Distribution. The pigeon tremex is found throughout Ohio 

 and is reported from many of the neighboring states and Canada. 



Natural enemy.- This insect has one very important parasitic 

 enemy, Thalessa lunator Fabr., sometimes known as the lunate long 

 sting. This is a. magnificent wasp-like insect having a body 

 about one and one-half inches long; attached near the tip of the 

 abdomen is a slender hair-like appendage about 3 inches long, and 

 though fragile in appearance the insect is able to drill the hardest 

 wood with it. During the drilling process the ovipositor describes 

 a graceful loop or arch over the back. Quite commonly the ovi- 

 positor becomes jammed in the wood and the insect perishes. 



By means of its drilling ovipositor, the long sting penetrates 

 the burrow of the pigeon tremex, deposits an egg therein which 

 later hatches into a grub that attacks the larva of the tremex. 



Control. Since the pigeon tremex prefers weakened, dying or 

 dead trees, steps leading to the maintenance of a vigorous tree 

 growth constitute one of the best control measures. Trees badly 

 attacked should be removed. 



THE MAPLE BOBEB 

 (Synanthedon acerni Clem.) 



Description. The maple borer is also called the maple sesian 

 and like ,many of the boring insects the rather characteristic work 

 is better known than is the insect itself. When the insect once is 

 recognized, however, it never will be forgotten. In the adult stage 

 the maple borer is a particularly beautiful wasp-like moth. The 

 wings are composed mainly of a clear membrane tinged with yellow 

 and hyaline ; the head is red as is also a conspicuous fan-like plume 

 at the tip of the body. The thorax and legs are a decided yellow. 

 The female moth measures about 1 inch across its expanded wings 



