DESCRIPTIONS OF AUSTRALIAN ^SCHNIN^E. 7 



sternite. Besides these, there can be distinguished in both sexes two smaller 

 appendages, often called "lateral," lying on either side of the median 

 superior appendage. These are the cercoids of Heymons ; they are not 

 functional in the larva, but give rise to the two superior appendages of the 

 male imago, or the two anal appendages of the female imago. In describing 

 exuviafj tlierefore, I prefer to speak of these as the involucra of the imaginal 

 appendages mentioned. 



Heymons * was of opinion that the so-called " inferior appendage " of 

 the male imago was developed from the base of the appendix dorsalis oi' the 

 larva — that is, from the eleventh tergite itself. This is very probably correct. 

 But, in all the male larvse of yftlsclinhuc examined by me, the involucra of 

 this appendage can be very clearly seen situated dorsally above the base 

 of the appendix dorsalis (see figures of Plate 7) ; and by comparison with the 

 same structure in the female nymphs^ I have come to the conclusion that 

 this involucre is truly an appendage or outgrowth of the eleventh tergite, 

 and not the tergite or base itself. If I am rioht in this view, it will add 

 weight to Handlirsch's t argument that the "cercoids'^ are the true "cerci'^ 

 regenerated ; for this dorsal involucre may then be considered as a regene- 

 ration of the " appendix dorsalis. ^^ The fact that the original and the 

 regenerated appendages exist side by side in the native nymph is not an 

 objection to this view ; because, there being no resting or pupal stage, no 

 other method of " regeneration " is available. In this paper, I shall speak 

 of this dorsal outgrowth above the larval superior appendage as the involucre 

 of the inferior appendage of the male imago, since it gives rise to that organ 

 in the male. 



The three " lamince anales " forming the " telson ^' are not mentioned in 

 this paper, since they cannot be seen in the yEsclinince except by removing 

 or opening out the larval appendages. 



By referring to Plate 7. figs. 1 and 21, the six appendages of the male 

 nymph can be easily localized ; 6' is the superior, i the inferior larval 

 appendage, while ms, mi indicate the involucra of the male imaginal superior 

 and inferior appendages respectively. 



Genitalia. — In full-fed nymphs, the males may be distinguished by a very 

 slight median tuberculation ventrally on the second and ninth segments. 

 That of the second indicates the beginning of the formation of the genital 

 fossa and its accompanying parts, and maj^^ be called the involucre of the 

 accessory genitalia ; that of the ninth is the rudiment of the gonapopliyses. 

 These involucra are too small to possess any taxonomic A^alue, and will not 

 be referred to in this paper. The female nymphs have no tubercle on the 

 second sternite, but a much larger swelling arising from the base of the ninth 

 is very distinctive and of great specific value. This is the involucre covering 



* Aim. Hofmu8. Wien, xix. (1904) p. 21. f Ibid. p. 59. 



