678 



FAMILY: TRICHOMONADIDiE 



has, however, been generally used for another group of flagellates owing to the fact 

 that Grassi (1881a) included in the genus a form which he called Monocercomonas 

 insectorum, a name which he regarded as including two flagellates previously named 

 by him (1879a) Schedoacercomonas gryllotalpce and S. melolonthct. Neither of these 

 is a Trichomonas, so that Grassi (188 1«) was quite wrong in placing them in his genus 

 Monocercomonas, which included a number of undoubted Trichomonas. In 1879, 

 however, he had given the name Betortomonas gryllotalpce to a flagellate of the mole 

 cricket, and as this name was placed before Schedoacercomonas gryllotalpw and 

 S. melolontha', both of which appear to belong to the same genus, the correct generic 

 name for these flagellates is Betortamonas, and not Monocercomonas. The question 

 was still further complicated by the fact that Grassi (1881a), without any apparent 



reason, altered the name Betorta- 

 monas gryllotalpce to Plagiomonas 

 gryllotalpce, which is therefore 

 merely a synonym. 



The flagellates of the 

 genus Retortmnonas are close- 

 ly allied to Eutrichomastix. 

 There are four flagella, one 

 of which is a trailing flagel- 

 lum. In the place of the 

 typical axostyle of Eutri- 

 chotnastix, there is a fibre 

 which stains deeply. In 

 many of the flagellates, how- 

 ever, such a fibre cannot be 

 distinguished, and they re- 

 semble Monadidee with four 

 flagella (see p. 308). The 

 first forms to be described 

 were Retortmnonas gryllotalpce 

 Grassi, 1879 (syns. Schedoacercomonas gryllotalpce Grassi, 1879; Monocer- 

 comonas insectorum Grassi, 1881, pp..; Plagiomonas gryllotalpce Grassi, 

 1881), of the mole cricket, Gryllotalpa sp., and R. jnelolonthce Grassi, 1897 

 (syns. S. melolonthce Grassi, 1879; M. insectorum, Grassi, 1881, p.p.) of 

 the cockchafer, Melolontha vulgaris. Parisi (1910) described as Tricho- 

 mastix orthopteronwi a similar form from the cockroach, while Jollos 

 (1911) gave the name Monocercomonas cetonice to one from larvse of Cetonia 

 sp. Hamburger (1912) also studied this flagellate. Mackinnon (1912) 

 observed a form in tipulid larvse, while Franya (1913) described forms from 

 Oryctes nasicornis, 0. grypus, and Phyllognatus silenus. Belar (1916) gave 

 a detailed account of the structure and division of R. orthopterorum. The 

 organism is pear-shaped as a rule, and measures 3 to 6 microns in length. 

 There is no cytostome (Fig. 281). Four flagella arise from the blepharo- 



FiG.281. — Betortamonas orthopterorum {x 3,800). 

 (After Belak, 1916.) 



1-2. Flagellates showing four flagella (one a trailing 

 flagellura), axostyle, nucleus, and blepharoplast. 

 3-5. Division stages. 



