Catalogue of Homoptera. 479 



frequently confounded by Mr. Walker in the most careless manner. 

 Apparently as if he were unacquainted with the distinction between a 

 solid body and a plane figure, terms belonging to one are frequently 

 employed as if they were terms belonging to the other : thus he uses 

 the term macula conica for what ought to be, I presume from the 

 insect, macula triangularis, margo convexus (or concavus) for margo 

 rotundatus (or sinuatus), caput hemispTicericum for semicirculare, itc. ; 

 very frequently the transverse nerAiires of the wings are spoken of 

 as upright, nervi erecti, and other nonsense. 



But we can only understand that the entomological papers of Mr. 

 Walker are of no scientific value whatever when we examine the 

 collections used by him. It will be found almost impossible to 

 determine from his descriptions alone such species as are not di- 

 stinctly marked by certain patterns of coloration, or by other similarly 

 striking characters, and that even in the case where these species 

 are placed (at hazard) in the genera, or at least in the group, or even 

 fiimily to which they truly belong. Species that are well defined 

 may be readily recognized by a description, if they are placed among 

 the group to which they in truth belong ; but if the species is placed 

 in another group, as a Chrysomela amongst Halticas, or a Vanessa 

 among Noctuas, it is impossible, even if the descriptions are truly 

 good, to identify it under that position. Any one who will take the 

 trouble to investigate the synonj-mical notes which I propose to 

 pubKsh will see that the same, frequently entirely well-known and 

 quite constant species is sometimes described /oi(r,^i'e, six, and even 

 eleven times over ! not only imder different specific names, but fre- 

 quently even as belonging to two or tJiree different genera ! and if 

 those species which would not to other entomologists probably pre- 

 sent even the slightest variety are to be found placed by him in the 

 same genus, they are often separated from each other by species that 

 have no affinity to them, and which often belong to other very 

 distinct genera. Sometimes species are described from specimens in 

 very bad condition, mutilated, or so much injured by having been 

 kept in spirits, that they are not suitable for any collection ; and 

 these cannot be determined in most cases even from the type-speci- 

 mens, much less with the help of the descriptions. Some of the iy[)cs 

 described are not in the collection of the Museum. 



A number of species are described as belonging to the genus 

 Elidiptera of Spinola, but of these not one truly belongs to that 

 genus, nor even to the group to which that genus belongs ; the 

 species that Mr. Walker has fancifully brought together as consti- 

 tuting this genus of Spinola belong, in fact, to seven different genera, 



