FROM THE SOCIETY S GARDENS. 



67 i 



1913 (9) I described them as present though modified in these 

 five genera (and in others) and figured them, at the same time 

 expressing the opinion that the apparatus was probably present 

 throughout the Mallophaga. Up to the present, after many 

 more dissections, thei-e is no reason for changing this opinion. 

 Recently (11, p. 393) Mr. Harrison has stated that the lyriform 

 organ is " totally absent " in Ornithohius. But it is still present 

 in this genus, though atrophied and very difficult to dissect out. 



Although in such genera as Lcemohothrion, Menopon, and Colpo- 

 cephcdnm the apparatus shows differences in the lengths of the 

 posterior and anterior cornua (often to a very great extent) and 

 in the shape of the " glands," the characteristic form of 13'riform 

 organ and *' glands " is preserved and is immediately recognisable. 

 In the following Amblyceran forms, however, very extensive 

 modifications have been brought about : — Boojjia and Iletero- 

 doxus (and probably the whole of the family Boopidpe), Oyropus 

 (probably all the Gyropidte), Pseudomenopon, AHtzschia, Trinoton, 

 Tetro]jhthalmus (belonging to the Menoponidse), Physostomum, 

 Trimenopon, AriGlstrona. Among the Ischnocera, the following 

 genera must be included : — Oniithohius, Aitatoecus, most of the 

 genus Ibidoecas probably, and the species Trichodectes hemitragi 

 Cummings and JVeophilopterus tricolor. Other forms, such as 

 Philopterus perticsus, are indicated by Snodgrass, but these 

 require investigation. 



Modification proceeds by way of the gradual disappearance of 

 the " nucleus" or rounded central portion of the lyriform organ, 

 the reduction of the " gland " in size and its ultimate dis- 

 appearance, and the transformation of "duct" and "glands" 

 into hypopharyngeal sclerites. In text-fig. 20 is shown the 

 lyriform organ of Ihidoecufi Jlaviis modified, but with the still 

 persistent remains of the "nucleus," consisting of a clear "pin- 

 hole " surrounded by a circle of dense cliitin. After bifurcating, 

 each branch of the "duct" enters a small, delicate, oval " gland," 

 which lies rather loosely encircled within a plate of chitin ; this, 

 behind, tails out in a narrow strip, and in front runs forward as 

 a broad hypopharyngeal plate in outline shaped like a human 

 thumb bent outwards with the " ball " of the thumb facing the 

 corresponding structure on the opposite side. Between the^e two 

 plates longitudinally runs a, narrow chitinous strip, just as in 

 Lipeuriis ferox and others. A sheet of transparent chitin crosses 

 between the two " glands," and in the centre of this may be 

 seen a small circular clear space, possibly a hole. 



As compared with this apparatus, that of /. platcdece is 

 decidedly more modified, all sign of "nucleus" having dis- 

 appeared ; while in a species from Aramics scolopaceus, appa- 

 rently undescribed, it is quite normal as in the majority of 

 Mallophaga *. 



* Mr. HaruiaoB iivforms. me that he possesses a species <5f Ihidcecus from an 

 Australian host with a normal Ivriform organ. 



