Nerve-winged Insects; Scorpion-tiies; Caddis-flies 233 



at night. It lives about sixty days, and then seeks a concealed place and 

 forms a spherical cocoon of sand and silk within which it pupates. 



Our three genera of the Ascalaphinae may be determined by the follow- 

 ing key: 



Eyes entire Pt yn.x. 



Eyes grooved. 



Hind margin of wings entire Ulula. 



Hind margin of wings excised Colobopterus. 



Under the loose hanging strips of bark on the eucalyptus-trees in Cali- 

 fornia or on the bark of various Pacific Coast conifers, as pine, spruce, and 

 cedar, one may often find certain odd, slender-necked, big-headed, gauzy- 

 winged, blackish insects about half an inch long (Fig. 324). A slangy student 

 once proposed the name "rubber-neck" for them, and it is a fairly fit one. 

 These "rubber-necks," or "snake-flies," belong to the family Raphidiidie, 

 of which but two genera are known in the world. The species of the genus 

 Raphidia have three simple eyes (ocelli), while those of Inocellia have no 

 ocelli. Twenty-four species are found scattered over Asia Minor, Syria, 



-^k^ 



Fig. 324. — Raphidia sp., adult, larva, and pupa. (Two and a half times natural size.) 



eastern Siberia, Europe, and England, while four species of Raphidia and 

 three of Inocellia occur in the western half of the United States. The 

 snake-flies are predaceous insects, the larvae being notoriously voracious 

 insectivores. The larvae live in crevices of bark, or under it, where 

 there are breaks in it, as is always the case on old trees of most eucalyptus 

 species. 



Snake-fly larvae are said to find and eat many larva; of the codlin-moth, 

 one of the worst pests of apple-trees. Many of the codlin-moth larvae crawl 

 into crevices in the apple-tree bark to spin their cocoon, and there meet 

 the hungry snake-fly larvae. 



The pupae (Fig. 324), which are not enclosed in silken cocoons like the 

 other terrestrial Neuroptera (ant-lions, lace-winged flies, Hemerobians), lie- 



