CASTES OF TERMOPSIS 497 



ing the body in bulk and partly decolorizing. Stained whole 

 mounts of the heads, showing the brain and eyes, are fairly 

 successful, and some whole mounts of njnnphs have been made, 

 but the stained whole mounts of the abdomen or entire insect that 

 have proved so useful in studying other termite genera have been 

 rarely successful with this genus. This may be due to the large 

 size, to the thicker skin, and the more abundant fat-body, but I 

 am inclined to attribute it in large part to the different chemical 

 composition of the Termopsis tissues, with consequent different 

 staining reaction from other termites. 



In the following pages the material described is Termopsis 

 angusticollis, but, although T. nevadensis has been less thoroughly 

 studied, enough has been done to state that the morphology of the 

 two species is very similar. 



THE CASTES 



Termopsis angusticollis Hagen 



T. angusticollis is the largest North American termite, the 

 body length of young first-form individuals, from the tips of the 

 mandibles to the end of the tenth abdominal segment, ranging 

 from 10 to 14 mm., and the head width from 2.1 to 2,8 mm. 

 The old enlarged first-form females attain a length of 15tol7mm., 

 and the males 14 to 15 mm. These figures show that the post 

 adult growth which takes place after mating is very slight in this 

 genus. The first-form males and females are active and of nearly 

 similar size throughout Ufe, for the Termopsis queens never 

 acquire the relatively huge bulk attained by the queens of the 

 smaller genera of the higher termites, such as Reticulitermes, 

 Nasutitermes, etc. It seems surprising at first that the egg-laying 

 queens of such a large termite should be of relatively smaller size 

 and greater activity; this, however, is merely an evidence of 

 the primitive character of the genus. The small bulk and the 

 activity of Termopsis queens may be due partly to the more or 

 less exposed habitat in wood above ground, partly to the lack 

 of the true work caste, but chiefly to the fact that Termopsis, in 

 common with other lower termites, still retains some of the 

 ancestral independence of the non-social insects. 



