Insects 177 



The latter, often found under dead animals, form the genus 

 Necrophorus, recognisable by the rather large size, and the black 

 and reddish-orange markings of the short truncated elytra. N. 

 tomentosus has the thorax above with much yellowish hair, but in 

 N. guttula and the closely related N. hecate, it is bare. The 

 species of Silpha or carrion beetles are broad and flattened. Our 

 commonest species is S. lapponica, first known from Lapland. 

 The broad thorax has thin yellowish hair; the elytra are dull 

 black, with raised lines or keels, and rows of tubercles between 

 them. 



Staphylinidae are usually known by the elongate form and 

 very short elytra, so that at first sight they appear not to be 

 beetles. In spite of the short elytra, the wings are well developed, 

 and the insects may often be seen in flight. In England there 

 is a minute species which habitually flies at dusk, at about the 

 level of the human head and causes annoyance by getting into 

 people's eyes. Most of the species are small, but the common 

 Creophilus villosus is considerably over half an inch long, and is 

 also distinguished by the abundant pale yellow hair on the second 

 and third abdominal segments. Our prettiest species belong to 

 Paederus, small and slender, head and end of abdomen black, 

 thorax and rest of abdomen bright ferruginous red, elytra steel 

 blue. The very small Staphylinidae are extremely numerous 

 and difficult to classify. 



Paussidae are small beetles, often with extraordinary an- 

 tennae, which occur in ant's nests. They are entirely absent 

 from the present fauna of the United States, but a genus (Paus- 

 sopsis), with two species, is found fossil in the Miocene shales at 

 Florissant. 



The water beetles belong to several families, the Dytiscidae 

 and Hydrophilidae being most common. In the former, the 

 slender antennae are eleven jointed, without hair; in the latter 

 the shorter antennae are six to nine jointed, the end joints forming 

 a hairy club. There are many other differences, showing that the 

 aquatic habit and similarity of external form has been acquired 

 quite independently in the two groups. In dealing with the 

 larger Hydrophilidae it is necessary to avoid mistaking the long 

 slender maxillary palpi for antennae. 



The Carabidae or ground beetles are extremely abundant 



