190 SUMMARY OF CURRENT RESEARCHES RELATING TO 



identical with that of the imago. The abdominal chffitotaxy and the 

 abdomen itself, however, undergo a very considerable metamorphosis at 

 the last ecdysis into the imago. The metamorphosis of all three shows 

 that there is a tendency for the hairs to develop from behind forwards, 

 inasmuch as the terminal pleura develop hairs while the rest are still 

 bare, and in P. oxyrrhynclius and P. spinuJosa the sterna are at first 

 also bare except in the last segment. There are always two hairs on 

 each tergum and sternum, if hairs are present at all. Some of these 

 early stages may represent stages in the phylogeny of the group, and 

 in this connexion it is suggestive to recall that the Anopluran genus 

 Linofinathiis is characterized by the large size of its spiracles and the 

 absence of abdominal plates, just as Pohjplax is characterized by the 

 small size of the spiracles and the presence of the plates, so that in 

 future it may be convenient to speak of the larva of Polyplax as the 

 " Linognathus larva." 



Respiratory System of Mallophaga.* — Launcelot Harrison gives 

 an account of the tracheal system of Myrsidea cucullaris, and takes a 

 comparative survey of what obtains in otiier types of Mallophaga. 

 The tracheal system of Mallophaga is disposed in two main trunks, 

 with stigmatic, dorsal, and ventral branches, with four narrow commis- 

 sures (neural commissures) in connexion with the main nerve masses, 

 and with, in primitive forms, a posterior abdominal commissure. The 

 stigmata are typically fourteen in numlier : one pair prothoracic, and six 

 pairs abdominal, usually dorsal, typically on segments 3 to 8. At least 

 two types of occluding apparatus are present. In the structure and 

 relations of the respiratory system the Mallophaga agree very closely with 

 the Anoplura, and also, in a more general way, with the wingless 

 Copeognatba. As the respiratory system is very uniform, such divergences 

 as do occur have considerable taxonomic interest. 



Mallophaga from Apteryx and their Significance. t — Launcelot 

 Harrison has found on skins of Apteryx (five species) at least three 

 species of Mallophaga, which he refers to the genus Rallkola Johnston 

 and Harrison. This genus includes Philopteridai of small to moderate 

 size ; of a general form between Philopterus and Degeeriella, but nearer 

 the latter ; without distinct clypeal suture ; with slight to well-marked 

 sexual dimorphism of the antennae ; with a definite indication of two 

 distinct articles in the tarsus ; with the transverse bands of the abdomen 

 continuous, or divided only by a narrow median line. But the best 

 characters are found in the male genitalia, which are very distinctive, and 

 in the genital plate and ventral pleural margins of the eighth segment of 

 the female, which have a very distinctive chsetotaxy. Harrison divides 

 the genus into three sub-genera — Rallkola s. str., confined to Rallidse ; 

 Parrkola, found on Parridse ; and Apterkola, on Apterygidae. 



The author presents the following argument : — Apterkola is a normal 

 parasite of Apteryx ; Apterkola is certainly, at most, a sub-genus within 

 the genus Rallkola ; Rallkola is a universal parasite of rails, and of 



* Parasitology, viii. (1915) pp. 101-27 (21 figs.), 

 t Parasitology, viii. (1915) pp. 88-100 (6 figs.). 



