ALDER-FLIES, SCORPION-FLIES. 33 



roof -like when at rest, the hind pair never folded. The tarsi have 

 five joints. The metamorphoses are complete. 



They are divided into ten families. 



The first family contains the Scorpion-flies, Panorpidce (1 335), Table- 

 so called from the curiously developed apex to the abdomen of the case 35. 

 males. They have the head prolonged downwards so as to form a 

 beak. The antennae are slender, composed of numerous joints. The 

 wings are rather narrow, with numerous cross nervures. 



The larvae feed in rotten wood. 



The British species are common in* woods. One curious genus, 

 Boreus (1346) is wingless. It is British and lives in moss, and 

 when walking much resembles a large flea. 



The Rhaphidiidce, (1347) are insects of rather small size, remark- 

 able for the length of the head and prothorax, whence their popular 

 name Snake-flies. The antennae are slender and composed of many 

 joints. The four wings are equal and nearly similar, with a glassy 

 appearance, the veins form a network. The larvae are very active, 

 carnivorous, living chiefly under loose bark of trees and logs. 



The Mantispidce, (1348) are at once recognised by the remark- 

 able form of the front legs which resembles those of a Mantis, 

 formed for seizing small insects. The head is free, transverse, with 

 rather large eyes. The antennae are not very long, composed of 

 many joints. The four wings are alike, equal, or with the hinder 

 pair slightly smaller, the neuration forms a delicate network. 



They are very numerous in tropical countries, and one is found 

 in S. Europe. There is no British representative. 



The eggs are laid with a threadlike attachment as by the Lacewing 

 flies. The young larva is very active. It attaches itself to the egg- 

 sack of spiders, which it enters and later on feeds on the young spiders. 

 It then changes its skin, completely alters its appearance, and is no 

 longer active. It changes to the pupa within the larval skin. 



The Nemopteridce are easily known by the great length of the 

 hind wings, which are very narrow, but sometimes dilated at the 

 tips. One of the longest is Halter imperatrix (1353) from West 

 Africa (fig. 33). Another remarkable form is one recently dis- 

 covered in Asia Minor, Chasmatoptera Sheppardi (1357). Species 

 of the genus Oroce have the hind wings almost thread-like. 



The neuration approaches that of the Ascalaphida, the fourth 

 vein commencing about the middle of the wing. 



The head is transverse with rather prominent eyes. The 

 antennae long or moderately long, slender. 



