IV. INSECTA: HEXAPODA, ARCHIPTERA. 



470 



pleted the metamorphosis but are in the wing-pad stage. The termites are 

 able, by quantity and quality of food, to modify the development of the 

 larvae and to determine which type of individual shall be produced. The 

 termites are farther noticeable for the bitter wars they conduct against 

 the true ants. Termes flavipes * in our northern states. T. fatalis, 

 Africa. 



Allied to the Termites are the often wingless PSOCID^, or book lice. 

 Trades divinatorius * is the book louse. Other species are winged and 

 live in moss, etc. Near here also belong the MALLOPHAGA, which, like 

 lice, live upon mammals and especially on birds. Like true lice they are 

 wingless, but they have biting mouth parts. Trichodectes* on the dog, 

 ox, etc.; Goniodes,* Docophorus* Nirmus,* etc., on birds. 



Sub Order II. AMPHIBIOTICA. The three families united here 

 differ much in structure, but agree in having aquatic larvae with tracheal 

 gills (fig. 495). These are ventral bushes in the Perlida3, wing-like or 

 bushy appendages of the abdomen in the Ephemeridae, and 

 three-leaved appendages in those Odonata which do not 

 respire by tracheal branches in the rectum. All of these 

 larvae are predaceous, especially the larvae as well as the 

 adults of the Odonata. The Odonate larvae have a peculiar 

 apparatus for the capture of prey. The mentum and sub- 

 mentum of the labium are greatly elongate and when 

 folded bring the tip like a mask beneath the mouth. The 

 ^ structure can be suddenly extended (fig. 507) and grasps- 



FIG. 507. 



FIG. 508. 



FIG. 507. Larva of ^schna grandis. (After Rosel von Rosenhof.) a 1 , a a , wing pads j 



m, mask ; st, spiracles. 

 FIG. 508. Ephemera vulgata. (From Schmarda.) The caudal bristles incomplete. 



the food. PERLID^E (Plecoptera) ; hind wings the larger. Perla* Ptero- 

 narcys* stone flies. EPHEMERID^E, fore wings large, the hinder small or 

 absent ; May flies, life very short in the adult state. Ephemera,* (fig. 508) 

 Cleon* Beetisca.* ODONATA (Libellulidse), wings nearly equal, the hinder 

 slightly larger ; Dragon flies, veritable insect hawks destroying numberless 

 mosquitos. LibelLula* JEsclma,* Agrion* Gfomphus.* 



Sub Order III. PHYSOPODA (Thysanoptera). Wings slender, fringed 

 with hairs ; tarsi bladder-like at tip ; mouth parts bristle-like, probably 

 used for sucking. The position of this group is very uncertain. Thrips,* 

 Limothrips* 



