39 2 



CAROLINE BURLING THOMPSON. 



with the third segment grooved and subdivided into two parts, 

 so that twelve and thirteen segments will be formed soon after 

 hatching. It is interesting to note the progressive development 

 of the termite order in as small a detail as the number of segments 

 in the antennae at the time of hatching. The Protermitidae 

 have nine antennal segments, with the third segment entire; in 

 the intermediate Mesotermitidae the number is still nine, but 

 the third segment is grooved or subdivided into two parts; in 

 the most highly developed Metatermitidae the number has 

 increased to eleven, with the third segment subdivided. 



d 



a 



FIG. 9. Eutermes pilifrons, newly hatched nymphs, a, head of reproductive 

 nymph; b, head of worker-soldier nymph; c, ovaries of reproductive nymph; d, 

 ovaries of worker-soldier nymph. Oc. 6, obj. 16, reduced one third. 



E. pilifrons, like all the other termites described in this paper, 

 has the two types of newly hatched nymphs which are alike in 

 external structure: the reproductive nymphs, with a large 

 brain and large sex organs (Fig. 9, a, c), and the w^orker-soldier 



