Nerve-winged Insects; Scorpion-flies; 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. Ptynx. 
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 Raphidiidae, 
of which but two genera are known in the world. The species of the genus 
Raphidia have three simple eyes (ocelli), while. those of Xnocellia have no 
ocelli. Twenty-four species are found scattered over Asia Minor, Syria, 
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 larvae 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 
