108 
The Respiratory System of Mallo^^haga 
stigmata in a few genera. Shipley (1909, p. 316) mentions that the 
prothoracic stigmata are difficult to see. It may be noted in passing 
that Kellogg (1903, p. 90) allows only five pairs of abdominal stigmata 
to Nesiotinus, but this is an error, as I have satisfied myself by personal 
examination, the six pairs being present in the usual position. (With 
the still more extraordinary error which has been made in describing 
the thorax of this insect I am not here concerned.) 
Figs. 2-8. Abdomen, to show stigmata, of: {2) Menopon; {^) Heterodoxus; (4) Bicinus; 
(6) Oyropus; (6) Lipeurus; (7) Gliricola; (8) Trimenopon. 
The abdominal stigmata are, with the exceptions mentioned above, 
constantly twelve in number. Their disposition differs in the two 
sub-orders. In the Amblycera (Fig. 2), with the exception of the 
Boopidae (including Boopia, Heterodoxus, and Latumcephalum) (Fig. 3), 
the Ricinidae (inc! tiding and Trochiloecetes) (Fig. 4), and Gyroptis 
(Fig. 5), the abdominal stigmata open upon the third to the eighth seg¬ 
ments. In the two families mentioned, in Gyropus, and in the whole 
of the IscHNOCERA (Fig. 6), the stigmata open upon the second to 
the seventh segments. In Gliricola (Fig. 7) and Trimenopon (Fig. 8), 
