Walter Ritchie 325 



disturbed or touched by the hand, they emit a fairly loud uniform chirping 

 noise which varies in intensity. This sound is produced through the 

 rubbing of the hind margin of the pronotum upon the central anterior 

 portion of the prolonged mesonotum. These two portions form the 

 stridulating organs and both of their surfaces are smooth and highly 

 polished. On the insect moving its head slowly up and down, friction 

 is caused by the rubbing of these two polished areas upon each other, 

 and as a result a noise is produced. The same sound can be produced in a 

 dead beetle by imitating this action. 



Pairing. The mating of the sexes takes place on the twigs and smaller 

 branches of the trees upon which they feed. On one occasion pairing was 

 found on a leaf. As a rule pairing occurs during the daytime and the 

 beetles may remain in copula over night; the length of the time two 

 beetles may remain coupled is extremely variable. 



The males seemed to outnumber the females. They certainly did in 

 the areas examined, where I estimated the proportion as 5 to 1. In my 

 opinion the males are attracted or guided to the females through sense 

 of smell. On one occasion I observed a male soaring in the air about 

 fifteen yards away make a direct flight towards a female, already attended 

 by two males, and alight beside her. 



Oviposition. The female deposits her eggs in the stems of vigorously 

 growing, healthy trees, and near the base. Prior to egg-laying, a pre- 

 liminary examination is made by the female of this portion of the stem. 

 During this survey she rubs the apex of her abdomen on the bark of the 

 stem, at the same time swaying her body from side to side. After testing 

 in this manner for a short time she crawls round and round the stem 

 often returning in the opposite way. Finally when satisfied, she chooses a 

 spot on the surface of the stem where the bark is smooth, and standing 

 with her body at right angles to the long axis of the stem, her antennae 

 directed backwards along the sides of her body, she gnaws a notch with 

 her mandibles. The incision lies typically in the vertical direction, but 

 sometimes is tilted slightly (Fig. 22). The cut measures on an average 

 about 4-75 mm. in length. The depth of the cut varies, but on an average 

 is about 2-25 mm. On very young stems, where the bast layers are thin, 

 the incision usually reaches the sapwood; on older stems, e.g. from 

 twelve years old and upwards, where the bast is thicker, only the outer 

 layers of the bast are cut. 



The time taken for completing the egg cavity is about ten minutes 

 or longer, and then the female turns round and backs into the excavation, 

 locating it with the tip of her abdomen. Next taking a firm hold of the 



