10 B. GRASSI AND A. SANDIAS. 



The ampulla also contains bacteria (Spirilla and Lepto- 

 thrix), which I have not specially studied, for they are not 

 absent in the complementary or substitute forms, and occupy 

 but little space. But it is crammed, so to speak, with Protozoa, 

 either Cercomonadidse (Monocercomonas, Dinenympha) 

 Pyrsonymphidee, or Lophomonadidse. Termites free from 

 Protozoa are generally distinguishable by the naked eye, on 

 account of the immaculate abdomen ; in those which possess 

 them the abdomen presents a more or less distinct yellow patch, 

 due to the caecum being visible through its transparent walls. 

 This patch derives its colour from the vegetable aliment of the 

 Termites, with which a large number of the parasitic Protozoa 

 are filled (see the Appendix) ; it is indistinguishable when the 

 food is colourless, and a Termite may then be supposed to be 

 free from Protozoa, whilst it is really harbouring an enormous 

 number. 



Protozoa are absent in the new-born larvse, and make their 

 appearance in Calotermes concomitantly with the appearance 

 of the four secondary Malpighian tubules, and with the ac- 

 quisition of a twelfth antennal joint, the third and fourth being 

 glabrous. These examples, described in the preceding chapter, 

 vary from 2" 5 to 3 mm. in length, and may possess either a 

 large or a small head. If the former is the case their am- 

 pulla is comparatively dilated, and contains both Monocer- 

 comonads and Lophomonads ; whereas those with a small head 

 contain Monocercomonads only, the Lophomonads first appear- 

 ing in a later stadium. 



Monocercomonads, Dinemympha, and Pyrsonymphidse begin 

 to appear in Termes lucifugus when there are twelve all 

 pilose antennal joints and eight Malpighian tubules, four large 

 and four small, and the body averages a little more than 2*25 

 mm. in length ; and they are sometimes present and sometimes 

 absent in such specimens. More precisely, they are generally 

 absent in small-headed and present in large-headed individuals; 

 but they are constantly to be found when the body length 

 exceeds 2*5 mm. 



The Lophomonadidse do not appear, at least as a rule, until 



