316 



known from several spots between Fiji and China. Other 

 species have an equally wide range. 



In working over a collection of Delphacidae from different 

 zoological regions one soon notices that there are numerous 

 cases of parallel development, both in structure and coloration, 

 which has no phylogenetic significance. The expansion of the 

 legs in Asiraca and PliyUodinus, and of the antennae in 

 Asiraca copiceras, Delphax and Purohita, the reduction of 

 both wings and tegmina, are a few such cases in structure. 

 In coloration it would be j)ossible to draw up a long list, of 

 which the following are a few : " Light carinae of head and 

 thorax with darker intercarinal spaces ; light spots on the 

 face ; light pronotum with dark mesonotum ; a dark spot on 

 metapleurum ; rings and longitudinal marks on legs ; a median 

 mark down frons, vertex and thorax ; a dark mark at end of 

 clavus and at end of costal cell ; these marks are often joined 

 by an ill-defined band ; and the ^'crescent" pattern on apical 

 half of teg-men. This last consists of a mark from costa over 

 cross-veins, along hind apical margin to apex or beyond ; this 

 pattern with an increase or decrease of infuscation, with hya- 

 line spots at the end of the apical cells and with the other 

 apical veins also fuscous, forms the markings of a great num- 

 ber of species of which the following list is but a few: Stohaera 

 concinna, Sogatopsis pralti. BainhusilHilii.s al hoi 'meatus. Del- 

 phax crassicornis , Peyl-'nislella rariegafa. P. pallidala^ PJiyllo- 

 dmus macaoensis. Aneefopia mandane, Kelisia fieheri, Bake- 

 rella maculata. Dicranotropis l-oehelel. D. pseudoinaidis. Pere- 

 grimis maidis, DelpJiacodes limhrda. 



I cannot accoiint foi- tliesc cases of parallel development 

 on any utilitai-ian i)rinci})al and if I must classify the process 

 it must be under some form of orthogenesis, which may give us 

 a name l)ut not an explanation. 



IJefore the species of the genus Delpliaeodes and its allies 

 can be straightened out it will be necessary to make more use 

 of the genitalia than has been u]> to the ])i'esent; not only the 

 pygophor, anal segment and genital styles but also the aedeagus 

 must l)e used. The last-named organ, I l)elieve, will give us a 

 better idea of relationsl)ip than any othei- single character. 



