DEVELOPMENT OF THE ANTENN.E OF TERMITES. 281 



that when Xll-jointed both III and IV are long joints, or 

 when XIII or XlV-jointed III is long- in the XIII and short 

 in the XIV expression; some go so far as to state that the 



XIII expression is due to the failure of III and IV of the 



XIV to sepai-ate. Generally, however, the descriptions are 

 not very illuminating. 



In the case of trinervif orniis the length of III in a XIV 

 expression may be very variable, as it depends upon the age 

 and activities of a particular community what the development 

 of III is. Similarly it depends upon the age and prosperity of 

 the community what the segmentation of the organ is. In 

 short, with this species the antennal features of the nasuti 

 depend to an exti-aordinary extent upon the nutritive factor. 

 Thus in very young colonies XII and Xlll-jointed antennas 

 are the more common, in older, XIII and XIV; whilst, in 

 established and- prosperous communities, XIV prevails and 

 may be accompanied by XV, especially with large indi- 

 viduals. 



The antennae ab ovo are definitely Xll-jointed and in 

 stage B. Their condition remains the same until after the 

 first ecdysis, and is as illustrated by fig. 10, g, h. At this stage 

 the flagellum is composed of 10 joints with the elements of 

 4 in the formative zone. After the second ecdysis the 

 antenna is XlV-jointed as in fig. 10, /; there being 12 

 joints in the flagellum with the elements of 4 in the formative 

 (stage E). The final antenna depends for its form upon the 

 developments of the third instar, and these may range from 

 stage E to G, the potential XVI-jointed pre-stage of H. 



In the progress of the third period of quiescency certain 

 changes take place, and with the ecdysis the organ virtually 

 acquires its adult expression. The elemental subdivisions in 

 III fuse to form a homogeneous whole or core. 



Small-sized nasuti will present, in the callow stadium, 

 antennas of the type represented by fig. 10, i. This, according 

 to the developed articulations, is a Xll-jointed organ, and is 

 so because two articulations have become suppressed, one 

 between (9) and (10), another between III and (11). The 



