DEVELOPMENT OF CASTES OF TERMITES. 389 



the two types, reproductive nymphs and worker-soldier nymphs. 

 Nymphs 2 mm. long with twelve antennal segments are differen- 

 tiated into "small-headed" and "large-headed" types. 



R. virginicus Banks. The newly hatched nymphs of R. 

 virginicus are I mm. long and have nine antennal segments, the 

 third grooved. They are differentiated into the two types of 

 large-brained reproductive forms and small-brained sterile 

 forms. The further development of this species, so far as I have 

 followed it, is very similar to and probably identical with that of 

 R. flaripes. 



R. n. sp. Banks. The young nymphs of a new species of 

 Reticulitermes not yet described have been given me by Mr. T. E. 

 Snyder. Examination of this species shows that the conditions 

 at the time of hatching are similar to those in R. flavipes and in 

 R. virginicus. It seems more than probable therefore that this 

 differentiation of the newly hatched nymphs into tw^o types is 

 common to all species of Reticulitermes. 



METATERMITID.E. 



Anoplotermes fumosus Miiller. The eggs of the Metatermi- 

 tidce are smaller than either of the other families of termites. 

 The eggs of A.jumosus measure from 0.56 to 0.60 mm. in length 



(Fig. i,/). 



FIG. 7. Anoplotermes fumosus, young nymphs i mm. long, with twelve antennal 

 segments, a, head of reproductive nymph; b, head of worker-soldier nymph. 

 Oc. 6, obj. 16, reduced one third. 



The youngest specimens of Anoplotermes fumosus that I have 

 examined are in an early phase of development, but, on account 

 of their size and the number of antennal segments, I do not think 



