13-2 Annals Entomological Society of America [Vol. IX, 



eration of those very factors which mark them off from the 

 other groups. The forms that have entirely lost their wings 

 have lost their capacity for producing sounds. In Ceuthophilus 

 the organs for the reception of sound have also been lost. The 

 factors by which we may divide the Locustidae from the Crickets 

 are not so conspicuous. The modification which the ovi- 

 positor has undergone in each group will suffice for their 

 division. The relative position of the bodies of the male and of 

 the female during copulation is another factor which may divide 

 them. The diversity found among the crickets makes further 

 subdivision possible in that group. The activities of the field 

 crickets may be regarded as the most typical for the Gryllidae. 

 The tree crickets (Oecanthinas) being specialized in their manner 

 of ovipositing are given a separate standing. The mole crickets, 

 because of the absence of the ovipositor, the changed manner of 

 depositing the eggs, and because of the development of a 

 chirping organ in the female, have been placed in a separate 

 division. Little is known of the reproductive habits of the 

 myrmecophilous crickets and Blattids. In European forms 

 only the females have been discovered. Both males and 

 females, however, have been found in an American form by 

 Wheeler. (Wheeler, 1900.) The reproductive activity must 

 differ somewhat from the typical mode. Consequently they 

 are given a separate rating as indicated in the diagram. 



Having made such a classification it must be admitted that 

 the behaviour of each group depends to some extent upon 

 structural characteristics so that the classification really rests 

 upon morphological characters, the basis ' "opted by tax- 

 onomists for cla-ssification. The structural characteristics 

 have been used, however, only when they have some intimate 

 connection with the reproductive behaviour. 



A glance at the ancestral tree of the Orthoptera, (Fig. 6), will 

 show some striking resemblances to the classification based 

 upon the reproductive behaviour (Fig. 5). The fossil evidence 

 bearing upon the ancestry of the Orthoptera has been thor- 

 oughly worked out by Anton Handlirsch ('08), and a genealog- 

 ical tree constructed to show the relations of the different fam- 

 ilies. Figure 6 represents the essentials of his scheme. The 

 Blattidas and the Mantidae are entirely divided off as early as 

 the Carboniferous period. The stock from which the other 

 groups have arisen was divided into two rather definite 



