414 tetch: 



of wood cells, but in the light of numerous contrary observa- 

 tions this must be regarded as exceptional. 



As an exception to the general rule, I have seen gelatinous 

 lichens eaten by the inhabitants of one particular nest ; but in 

 the majority of cases the insects have attacked crustaceous 

 species of the type referred to. The green alga3 which clothe 

 damp flower pots are consumed by them, and they appear to be 

 especially fond of the orange filamentous alg?e {Chroolepis 

 spp.), which are fairly common on tree trunks in the Tropics. 

 But they do not relish fungi alone : Mdiola, for example, they 

 will scarcely touch, even when no other food is availal)le (see 

 later) ; and this leads one to suppose that it is the algal rather 

 than the fungal element of the lichen which attracts them. 



Wien thev have reached their feedinsf ground, the insects 

 congregate upon the suitable lichens, and make no attempt to 

 gather the other species. With their mandibles, small frag- 

 ments of the lichen are scraped off and gathered into balls 

 about 1*5 mm. diameter. The largest I have seen measured 

 2 '25 X I'-'j mm. The worker then marches off to the nest, 

 holding the ball in its mandibles. As far as I have been able 

 to ascertain, the workers load up the one which acts as carrier, 

 adding particles until the ball is the proper size. When 

 thousands of them are scraping away the lichen at the same 

 time, a rasping sound can be heard distinctly. Fragments of 

 bark, or epidermis, are sometimes scraped off with the lichen, 

 and may be detected in the material of the comb ; l)ut as a 

 ruU- the insects succeed in removing the lichen without any 

 trace of the host plant. 



The termites have not yet been watched all night, and 

 thorefon! tlierc is some doubt as to the actual conduct of the 

 proccHsion. From what I have seen it ^\ ould ap])ear that there 

 Ih a continuous movement to and from the nest during the whole 

 time. Dr. JJugnion's account convej's the ijnpression that in 

 the instances observed ])y him there was an interval of several 

 hours between the outw;ird and homeward processions, and 

 during that time no termites were seen on the track, i.e., that 

 the outward and homeward jjnxiessions arc indejiendent move- 

 ments undertaken by all 1 he insects at the same time. But in 

 the onrly morning n stream of woikers may be seen travelling 



