3 88 



CAROLINE BURLING THOMPSON. 



MESOTERMITID/E. 



Arrhinotermes simplex Hagen. The eggs of the Mesotermitidse 

 are considerably smaller than those of the Protermitidse. 

 The eggs of Arrhinotermes simplex measure from 0.8 to I mm. in 

 length and are slender and reniform (Fig. I, d}. 



The newly hatched nymphs are about 1.2 mm. long, and have 

 nine antennal segments, the third segment grooved and sub- 

 divided into two parts. 



The two types of nymphs: (a) reproductive nymphs, with large 

 brain and large sex organs (Fig. 6, a, c), and (b) worker-soldier 



d 



FIG. 6. Arrhinotermes simplex, newly hatched nymphs, a, head of reproduc- 

 tive nymph; b, head of worker-soldier nymph; c, ovary of reproductive nymph; 

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



nymphs, with small brain and small sex organs (Fig. 6, &, d), 

 are likewise present in this genus at the time of hatching; and 

 with an increase of the body length to 2 mm., the "small-headed " 

 and "large-headed" nymphs are differentiated. There is a 

 striking resemblance between the young of this genus and the 

 related genus Reticulitermes . 



Reticulitermes . 



R. flavipes Kollar. 1 The egg measures from 0.68 to 0.7 mm. 

 (Fig. i, e). The newly hatched nymphs are i.i mm. long, with 

 nine antennal segments, the third segment grooved, and are of 



1 For a fuller description of the development of R. flavipes, see Thompson (1917)- 



