LIGHTXIXG BEETLES. 39 



the apex, and by the basal joints of the front tarsi of 

 the males. These joints are not squared, like those of 

 the Chlaeniidae, but are somewhat heart-shaped, and 

 furnished with two rows of bristles beneath. 



Our first example of this family is the Beetle 

 which is known to entomologists by the name of 

 PterosticJms madidus, a figure of 

 which is given herewith. The 

 colour of the insect is shining 

 black, with a slight brassy gloss. 

 The smooth head has two impres- 

 sions in front ; the thorax is con- 

 vex and narrow behind, with a 

 bold central furrow and a deep 

 wrinkled pit at each angle. A lens 

 is required to make out these 

 details. The elytra are covered Pterostichus 

 with regular striae, a circumstance which has gained 

 for these insects the generic title of Pterostichus, or 

 ' streaked-wing.' There are a few small punctures on 

 each elytron, and a row of bold punctures runs along 

 each margin. The wings are not developed. 



This is a very common insect, and can be taken 

 in any number, as it runs boldly about. Anglers 

 often use it successfully as bait. Although devoid of 

 wings, it is very quick on its legs, darting about with 

 such velocity that the generic name of Steropus, or 

 ' lightning,' was once applied to it and another allied 

 Beetle. 



Twenty-two British species of this genus are now 

 acknowledged, but in it are merged several genera of 

 the older entomologists. 



