672 CLASS IV. INSECTA. 



and Turkestan. P. migratorioides is E. African. P. marmoratus s 

 widely found in the warmer parts of the East, whilst P. nigrofasciatus 

 spreads into colder regions. Schistocerca peregrina reaches from N. Africa 

 to N.W. India and is probably the " locust " which plagued Pharaoh and 

 his people. S. americana is migratory in the United States and several 

 other species are American. The Rocky Mountain Locust is Caloptenus 

 spretus. 



The Acridiidae comprise the following nine sub-families : 



1. Tettiginae. In this large sub-family the pronotum is extended 

 backwards as a hood or cover over the body, and this extension often 

 takes a grotesque and bizarre form. A similar outgrowth occurs in 

 the Membracides, a sub-family of the Hemiptera. Tettix bipunctatus 

 and T. subulatus are British. Xerophyllum ; Cladonotus ; SceMmena. 



2. Pneumorinae. Large South African forms with few species. 

 Pneumora. 



3. Mastacinae. Rare and tropical. Mastax. 



4. Proscopiinae. Wings small or absent. The insects frequently 

 resemble Phasmids, but here it is the prothorax which is elongated. 

 Cephalocoema. 



5. Pyrgomorphinae. PyrgomorpJia. 



6. Tryxalinae. A numerous sub-family. Mecostethus grossus is 

 British ; Tryxalis. 



7. Pamphaginae. Chiefly African and Mediterranean. Xipho- 

 cera. 



8. Oedipodinae. This sub-family includes most of the migratory 

 locusts of the Old World. Pachytylus ; Methane ; Cuculligera ; 

 Trachypetra. 



9. Acridiinae. Most British Orthoptera belong to this sub-family. 

 Stenobothrus with six British species ; Gomphocerus with three ; 

 Acridium ; Caloptenus. 



Fam. 7. Locustidae.* Long, slender antennae of more than thirty 

 segments ; elongated, flattened and sword-like ovipositor ; tarsi with 

 four segments ; auditory organs on tibiae of first legs ; wingless forms 

 numerous. 



The Locustidae f are as a rule more delicately formed insects than the 

 Acridiidae, are destitute of the tracheal air- vesicles, and do not take 

 such prolonged flights as true locusts. The term " grasshopper is applied " 

 indiscriminately to certain members of both the families Acridiidae and 

 Locustidae. The shrill music of the Locustidae is. produced by rubbing 

 a file-like ridge beneath the base of the left tegmen over a ridge on the 

 upper surface of the right tegmen. This apparatus is usually confined 

 to the male. The ovipositor is sometimes as long as the body, or longer, 

 and is used in placing the eggs in the earth or in slits made in stems of 

 plants. Most of the insects pass the winter in the egg, and hatching out 

 in the spring, become adult in about ten weeks after casting the skin 

 which the young insects economically eat some four or five times. The 

 Locustidae are largely nocturnal ; they frequent trees and live largely on 

 leaves, but they are not bigoted vegetarians and some are said to be 



* Dewitz, Zeitschr. wiss. Zool. xxv, 1875, p. 174. Riley, Ann. Rep. 

 Insects, Missouri, vi, 1874, p. 159. 



t The family name is unfortunate as " locusts " belong to the Acri- 

 diidae. Some authorities substitute the name Phaseonuridea. 



