62 Bulletiìi de In Société Eìitomoìogique d'Egypte 



In addition to determining the total increase of 

 the antenna during tlie post-embryonic development : 

 70 minus 6.5 = 63.5 mm., I have attempted to deter- 

 mine the increase due to the greater ninnber oF joints 

 and that due merely to the lengthening ol the joints. 



For this purpose I took the male antenna of 178 

 joints referred to above and measured four portions 

 each composed of 44 joints, corresponding in number 

 to the last 44 of the newly hatched insect, the first 

 three being in each case omitted. The followinfr 

 measurements were obtained : 



Joints 4- 47 Lengtli 11 mm. 



)) 48- 91 » 15 ). 



). 92-136 » 19.5 » 



>> 135-178 » 22.5 » 



Tola! » 68 » 



These figures show^ that the 44 terminal joints 

 which are the oldest and have had most time to 

 grow, are together twice as long as the most 

 recently formed joints 4-47. 



It is further apparent that in spite of the enor- 

 mous difference in size belween the two insects these 

 last joints are barely twice as long as the 44 terminal 

 joints of the newly hatched larva, their lengths being 

 11 and 6 mm. respec lively. 



Further, an examination of the antennae under 

 the microscope reveals the fact that the lengthening 

 of the joints is relatively quicker in the young larva. 

 For example the joints 30-47 are in this case twice 



