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 larvas feed in rotten wood. 



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

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

 when walking much resembles a large flea. 



The Rhaphidiidce (1 347) are insects of rather small size, remark- 

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

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

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

 appearance, the veins forming a network. The larvas are very 

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



The Mantispidoz (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 antennas 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. 



The eggs are laid with a threadlike attachment as by the Lace-wing 

 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 and completely alters its appearance, and 

 is no longer active. It changes to the pupa within the larval skin. 



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

 in S. Europe. There is no British representative. 



The Nemopteridm 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 Groce have the hind wings almost thread-like. 



The neuration approaches that of the Ascalaphidce, 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. 



D 



