REPORT OF THE SOCIETY 101 



Upon the tree and she at once began to oviposit. Some of the eggs were laid 

 upon the smooth bark, others about the edges of the tin, but most were stored 

 away in crevices and cracks, eight, ten and more, tightly wedged together. 



There were three or four pairs of moths placed in glass cages at the labo- 

 ratory for egg records, etc. No evidences of mating were noted in confinement, 

 although the males frequently were active, circling around and keeping up a 

 high beating hum with their thin parchment-like wings, only to be totally 

 ignored or pushed aside. After a day or two the mahs died, but the females 

 lived for eight or ten days longer to oviposit. Egg records in this connection 

 will be found tabulated below. 



Females enclosed in wire cag36 in the open were frequently visited by males, 

 and se\^eral were caught in this way. There were also occasions where males 

 were noticed on the outside of the wire screen of the insectary. Likely they 

 had been attracted there by the females within. 



EGG 



The egg is somewhat oval in shape, averaging 2.34 mm. in length and 1.78 

 mm. in width. The whole surface of the chorion is heavily, irregularly reti<^ula- 

 ted, except at the poles where a small circular area is free from these markings. 

 When first laid they are dull greenigh-^'ellow, but later this colour changes to 

 a full brown with suggestions of a greenish tint in some instances, and in 

 others a dark muddj'-yellow. 



OVIPOSITION 



This begins shortly after the female has emerged from the pupal case. 

 The moth starts by carefully examining the surface of the logs or trunk 

 which it is on, testing every crack and crevice of the bark, and by means 

 of the long ovipositor which is quite freely used, it endeavours to find some 

 convenient spot to place a batch of eggs; then extending the ovipositor 

 deeply into the crevice will pack away two, three, four and ev^en more eggs 

 according to the size of the cavity. In some cases as many aiS twelve have been 

 counted tightly wedge together. After deposition in one place the moth will 

 move to a fresh site and repeat the operation. Occasionally, it stops awhile as 

 if to rest, then starts up again. A clear viscous liquid is often present in suffi- 

 cient quantities to moisten small spots on the wood surface. This, is likely, 

 used for glueing the eggs to the bark as it was never noticed except during 

 oviposition. When depressions, crevices or such hiding places are not accessi- 

 ble, eggs may be laid indiscriminately upon the smooth bark, or in small 

 groups moj-e or less irregular in number a,nd scattered. 



All the eggs are not expelled at one time* usually a week will cover these 

 activities. The laborator}^ daily records in this conection show a sharp curve 

 upwards, then a gradual decline. The number of eggs per female varies conside- 

 rably from 50 to over 275. From two unfertilized females which were dissected, 

 74 and 132 ova, respectively, were taken in advance stages, with many smaller 

 ones and a number in the early embryonic formations which were not counted. 



Dr. James S. Bailey in U. S. Bull. 3, Dis^. Entom. p. 53 briefly remarks 

 as follows: — "Cossns robiniae Peck and Cossus querciperda Fitch have been 

 known to extrude upwards of three hundred ova". It may be safe, therefore, 

 to place two hundred and fifty eggs ag a fair average per female. The female 

 dies almost at once after oviposition has terminated. 



