72 



INTKODUCTIOF. 



II. Elytra covering, or almost entirely covering, 

 the abdomen ; dorsal segments of abdomen 

 (except where exposed, at apex) mem- 

 branous. 



i. Antennas not geniculate. 



1. Wings in part or entirely fringed with 



longer or shorter ciliate hairs ; size 

 very small. 



A. Posterior coxae laminate ; insects, as 



a rule, capable of rolling themselves 



into a ball Clambidae, p. 85. 



B. Posterior coxae not laminate. 



a. Antennas verticillate, with long- 



hairs ; wings with long fringes 

 of hairs ; tarsi three-jointed ; form 



almost always oblong Trichopterygidae, 



b. Antennae loosely clavate, without [p. 86. 



long hairs ; wings with much 

 shorter fringes of hairs ; tarsi 

 four-jointed, (third joint very 

 small) : form more or less hemi- 

 spherical Corylophidae, p. 88. 



2. Wings without fringes of hairs. 



1. Posterior coxae slightly transverse, 



conical, small ; eyes coarsely granu- 

 lated. ; size, as a rule, very small . . Scydmaenidae, p. 82. 



2. Posterior coxae strongly transverse ; 



eyes finely granulated (sometimes 

 absent) ; size, as a rule, large or 

 moderate. 



A. Posterior coxae contiguous or only 



slightly separated , Silphidae, p. 83. 



B. Posterior coxae widely separated . . Scaphidiidae, p. 90, 



ii. Antennae geniculate. 



1. Head and mandibles normal ; tarsi 



short Histeridae, p. 91. 



2. Head very large, as long or nearly as 



long as prothorax ; mandibles perpen- 

 dicularly reflexed ; tarsi very long 

 and slender Niponiidae, p. 93. 



Family 11. STAPH YLINIM5. 



Elytra very short, leaving the greater part of the abdominal 

 segments exposed, except in very few cases (e. g. Omalium) in 

 which only the apical segments are uncovered ; abdomen or hind-body 

 usually elongate and more or less parallel-sided, with ten dorsal and 

 seven or eight ventral segments, cdl entirely corneous, even when more 

 or less hidden by the elytra (except in Homalota, where the first 

 secpnent, which is almost or quite concealed by the elytra, is semi- 

 membranous ) ; head very variable in size ( often varying in the 

 sexes ) ; antennas variable in insertion and form, eleven-jointed or 

 ten-jointed, filiform, subclavate or clavate ; prothorax strongly 



