420 



ARTHROPODA 



and females. A colony of termites, consisting usually of thousands of individuals, 

 forms a nest with numerous chambers and passages. They are nocturnal, and 

 they burrow, without coming to the surface, through old wood (timbers of houses, 

 furniture, picture frames, dead wood in the forest, etc.). They line these 

 chambers with a cement-like substance composed of refuse which has passed 

 through the alimentary canal. Many species build dome-like nests, ten or 

 fifteen feet high, of chewed earth. In a colony are winged and wingless indi- 

 viduals, the latter with ametabolous development (fig. 464). The wingless 

 forms have the sexual organs rudimentary, but, in contrast to ants and bees, 

 may belong to either sex. They are frequently blind, have strong mandibles, 



and are of two kinds, the workers (c) and the large- 

 headed soldiers (d). The winged forms are sexually 

 functional (b). Shortly after the metamorphosis they 

 swarm, and then the wings are bitten off at the base and 

 'king' and 'queen' either form a new colony or enter one 

 already in existence. After copulation the abdomen of 

 the queen, by the formation of numerous eggs, swells to 

 an enormous size (e). Since the swarming individuals 

 form the prey of birds and other animals, it often hap- 

 pens that a colony is left without a royal couple. In 

 such cases the line is perpetuated by reserve males and 



FIG. 465. FIG. 466. 



FIG. 465. Larva of jEschna grandis (after Rosel von Rosenhof). a 1 , a'-, wing pads; 

 m, mask; st, spiracles. 



FIG. 466. Ephemera vulgata (from Schmarda). The caudal bristles incomplete. 



females, sexual animals which have not completed 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. 



Allied to the Termites are the often wingless PSOCHXE, or book lice, Trades.* 

 Other species are winged. Near here belong the MALLOPHAGA, bird lice, which 

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

 but have biting mouth parts. Trichodectes,* dog, ox, etc; Goniodes* Nirmus* 

 etc., on birds. Sub Order II. AMPHIBIOTICA. The three families differ 

 in structure, but agree in having aquatic larvae with tracheal gills (fig. 453). 

 All of these larvae are predaceous; Odonate larvae have a peculiar apparatus for 

 capture of prey. The mentum and submentum 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. 465) and grasps the food. PER- 

 LID.E (Plecoptera) ; hind wings larger. Perla,* Pteronarcys* EPHEMERID.E, 

 fore wings large, hinder small or absent; May flies. Ephemera* (fig. 466), 

 liii-lisca* ODONATA (Libellulidae) , wings nearly equal, hinder slightly larger; 

 dragon flies, veritable insect hawks destroying numberless mosquitos. Libel- 

 //</,* Eschmi* Agrion*. Sub Order III. PHYSOPODA (Thysanoptera). 

 \Yings slender, fringed with hairs; tarsi bladder-like at tip; mouth parts bristle- 

 like, probably used for sucking. Position uncertain. Thrips* 



