PROC. ENT. SOC. WASH., VOL. 21, XO. 5, MAY, 1919 99 



It might be stated in connection with the biology of termites 

 that all subterranean, earth-inhabiting termites have a worker 

 caste in colonies; while none of the primitive wood-inhabiting 

 species which do not live in the earth have a worker caste with the 

 exception of Prorhinotermes simplex Hag. of the sea coast of southern 

 Florida and the keys. 



Sense Organs. 



Stokes (1.S93) records highly specialized sense organs on the 

 legs of R. flampes. Grassi (1893) mentions tactile "very long, 

 fine, readily vibratile" hairs on the body and states that the 

 cerci also appeared to be essentially tactile. Snyder (191.1) 

 states in regard to these highly specialized sense organs: 



"It is believed that there is a relation between the convulsive movements 

 frequently observed, that is, the sudden jerking of the whole body, and these 

 sense organs, and that individuals are thus enabled to communicate, or at 

 least give danger or distress signals. The convulsive movements made by 

 the workers and soldiers, when the royal pair are disturbed in the cell, are 

 very violent and indicate great agitation. 



There is a characteristic musty or acrid odor which can be easily detected 

 in colonies of Leucotermes \Rcticiditermes], and individuals frequently can be 

 MTU to follow directly in the path taken by others, but as termites usually 

 travel in well-worn channels this may be due to tactile sense alone." 



Body Pigment and Eyes. 



In species of termites which live in wood but not in earth, 

 certain castes have a more deeply pigmented body than usual; 

 these are the third form reproductive individuals of Termopsis, 

 the soldiers and third form reproductive individuals of Kalo- 

 termes, and the workers, soldiers and third form reproductive 

 individuals of Prorhinotermes simplex. The castes of the sub- 

 terranean genus Reticulitermes have pale or dirty white bodies, 

 except the winged adults, w r hich at the time of swarming have 

 a dark brown skin, although later, after the underground life- 

 has begun, even this caste may lose some of its pigment. 



The compound eyes and the ocelli are large and well developed 

 in all the castes of P. simpler, a species which lives in dead tree 

 trunks or logs, so that there seems to be a correlation between 

 the high state of development of the eyes and the habitat of 

 these insects. 



In the subterranean Reticulitermes there are evidences of loss 

 of pigment and the structural elements of the eyes in all castes 

 except the winged insects. 



\Yheeler states (1913) that of the four groups of social insects 



