IV. INSECTA : HEXAPODA, COLEOPTEEA. 



483 



parts, predaceous. Chrysopa* feeds on plant lice ; Myrmeleo* ant lions; 

 larvae dig funnel-like pits in sand and capture the ants, etc., which fall 

 into them. PANORPIDJE (Mecoptera) ; mouth prolonged into a rostrum ; 

 Panorpa, *Bittacus* 



Sub Order II. TRICHOPTERA (caddis flies). Wings usually large ; 

 mouth parts rudimentary, forming a short sucking tube which, with the 

 wings covered with hair-like scales, recalls the Lepidoptera ; larvae aquatic 

 with tracheal gills ; build cases of foreign matter, stones, sticks, etc., in 

 which, like a hermit crab, they live ; pupation occurs in these tubes. 

 Phryganea * (fig. 512), Hydropsyche* 



Order V. Strepsiptera. 



These forms, comprised in a single family, STYLOPID.E, are parasitic on 

 the Hymeiioptera. The six-legged larvae (fig. 513, 3} press in between the 

 ventral abdominal plates of bees or wasps and pupate there. The quickly 



FIG. 513. Xenos rossi. (After Boas.) 1, female : , male ; 3, larva ; /-/// thoracic 

 somites ; a 1 , rudimentary fore wing ; a 2 , hind wing. 



flying male (2) escapes from the pupal skin ; it recalls somewhat a beetle ; 

 has small fore wings and large hinder ones. The wingless, legless female 

 (1) remains in the pupal skin and is fertilized there ; she is viviparous. 

 Insects infested with these parasites are ' stylopized.' The affinities of 

 the order are doubtful. The forms are frequently included with the 

 beetles. Stylops,* Xenos.* 



Order VI. Coleoptera. 



The beetles are the highest of the Hexapoda with biting moutb 

 parts. They are closest to the Orthoptera, as is shown by the 

 structure of mouth parts and wings. The mandibles are strong; 

 the maxillae (fig. 514) have lacinia and galea; the labium consists, 

 of a submentum (often called mentum), behind which the rudi- 

 mentary mentum with its palpi, paraglossae, and glossae (the latter 

 frequently fused to a ligula) are retracted. (In the genus 

 Nemognatha the maxillary galea form a sucking organ.) The 

 group is distinguished from the Orthoptera by the holometabolous 

 development with pupae liberae, while the larvae (fig. 500) show 

 many modifications corresponding to the mode of lite. Another 

 character is afforded by the wings. The anterior pair, separated 

 at the base by a scutellum, are hard elytra not fitted for flight, and 



