8 



tiiey are only a prolongation and intensification of the minute 

 corrugations that border the hind margin c,f the wing from the 

 end of the costal margin to the base of the wing. 



"In another, {i.yricci imfluinii, PI. 20 figs. 3-s), from Fiji, 

 the proportional size of the tegmina to the wings is more normal, 

 about 73/ to s'A, and the anal areas of the latter are normal, 

 bearing a strongly corrugated patch near the basal edge. 



"Upon examining the anal area of the wing of Perkliisiclla 

 saccharicida, an enlarging of tiie corrugation along the basal 

 portion of the tdge can be seen. I am in doubt if this could be 

 the means by which they produce the sound." 



(PI. 20 figs. 1-2 represents the wings cf Pyrr/toiinira citha- 

 rista). Mr. Muir, also, before leaving for the Orient, left me 

 some mounts of tegmina and wings, from which IM. 20' figs. 1-9 

 have been made. 



I have exam.ined a considerable amount of material and find 

 the stridulatory area developed as follows: 



In most of the Derbidae and in some Asiracidae, this structure 

 is present, in both sexes. I cannot find it in any other Auc- 

 henorhynchi, nor in those Asiracids in which the wings are rudi- 

 mentary. 



Since my last memoir, Froggatt has published "Australian 

 Insects" (1907), in which there are short biologic notes on sev- 

 eral Homoptera. 



