333 



ORTHOPTERA 



FIG. 210. Rhipipteryx sp., 

 Amazon valley. 



lidae is very doubtful. 



compose it are rare in collections, their saltatorial powers no 

 doubt making it difficult to catch them ; little is known as to 

 their habits. In the undescribed Ama- 

 zonian species we figure (Fig. 210), the 

 wings, instead of being mere rudiments, 

 as in Tridactylus, are elongate and project 

 beyond the body ; they are of a blue- 

 black colour, and arranged so as to look 

 as if they were the abdomen of the Insect ; 

 they, moreover, have a transverse pallid 

 mark, giving rise to an appearance of 

 division. It is difficult to form any 

 surmise as to the nature of so curious a 

 modification of the wings. 



The Tridactylides have no tympana on 

 the legs, and their affinity with the Gryl- 

 Dufour thought T. variegatus to be more 

 allied to the Acridiidae. He based this opinion chiefly on some 

 points of the internal anatomy, but pointed out that Tridactylus 

 differs from the Acridiidae in having no air - sacs in the 

 body. 



Not many of the Gryllidae are so peculiar as the forms we 

 have mentioned. The family consists in larger part of Insects 

 more or less similar to the common cricket, though exhibiting 

 a great variety of external form. The common cricket of our 

 houses, Gryllus (Acheta) domesticus (Fig. 204), has a very wide 

 distribution in the Old World, and is also found in North America. 

 It is believed to have had its natural distribution extended by 

 commerce, though really nothing is known as to its original 

 habitat. The shrill chirping of this little Insect is frequently 

 heard at night in houses, even in the most densely inhabited 

 parts of great cities. Neither the female nor the young are 

 musical, yet the chirping may be heard at all seasons of the year, 

 as young and adults coexist independent of season. The pre- 

 dilection of Gryllus domesticus for the habitations of man is very 

 curious. The Insect is occasionally found out of doors in the 

 neighbourhood of dwelling-houses in hot weather, but it does not 

 appear that this species leads anywhere a truly wild life. It is 

 fond of heat ; though it rarely multiplies in dwelling-houses to 

 any great extent, it is sometimes found in profusion in bake- 



