SYNOPSIS OF SPECIES OF LISTRUS 175 



Ceruicalis at first sight resembles montanus Casey ; in the former the 

 maculation is more distinct, pronotum broader and more convex and the 

 fifth ventral segment is modified in the male, besides there is a tendency 

 for the elytral maculae to unite to form five transverse dark fasciae, which 

 are frequently in evidence and unique. 



SYNOPSIS OF THE SPECIES OF LISTRUS. 



The species of Listrus may be divided into two Sections as follows : 

 Fifth ventral abdominal segment in the male, truncate or sinuato- 



truncate at apex Section I 



Fifth ventral more deeply sinuate and modified on the disk in the male Section II 



The species can be arranged in the following Groups : 



SECTION I. 



Elytral apices different in the sexes Definitus Group 



Elytral apices similar in the sexes 1 



1. Eyes very prominent and more strongly convex in anterior two-thirds; 



head broad, male Cephalicus Group 



. Eyes moderately prominent and evenly convex 2 



2. Elytral pubescence unicolorous Senilis Group 



. Elytra ornate with a pattern of blackish or brownish-black hairs 3 



3. Elytral pubescence very short, pattern very obscure from sparseness of 



pale hairs Punctatus Group 



. Elytral pubescence longer and more abundant, pattern distinct 4 



4. Elytra with three rather wide transverse black fasciae, the basal of which 



may be more or less interrupted Annulatus Group 



. Elytral fasciae more or less modified or broken up 5 



5. Species with legs more or less piceous or rufo-piceous, femora never 



pale DifHcilis Group 



. Species usually scarcely over 2.5 mm. in length, except luteipes (3 mm.) ; 

 legs entirely pale; basal and post-basal fasciae broken up into variable 

 small maculae Luteipes Group 



SECTION II. 



Metatrochanters triangular Trochantericus Group 



Metatrochanters of the usual form, suboval 1 



1. Pubescence short and sparse, elytral pattern obscure but discernible 



Liebecki Group 



. Pubescence longer, elytral pattern distinct 2 



2. Elytral maculation tending to form fasciae and nearly constant in charac- 



ter -- Interruptus Group 



. Elytral maculation consisting of isolated maculae tending to obsolescence 



Salicis Group 



DEFINITUS GROUP. 



Elytra with a wide subapical black fascia; apices acuminately produced in the 

 female and rounded as usual in the male; pronotum longer than wide; 

 legs entirely pale 1. definitus Fall 



