2 0RTHOP1 KK.\ 



In classification the head affords several features of taxonomic importance, the shape and si/< oi 

 the head itself being used in some cases for specific differentiation. The most important characters oi 



the head, however, as used in the determination of genera and highei groups lie in the shape and position 

 of the fastigium of the vertex, that of the "face, the position of the occiput and the place of insertion oi 

 the antennae. In some groups the fastigium of the vertex is horizontal and often considerably extended 

 (Plate, Fig. I), while in others it is nearly vertical and rounded (Plate, Fig. 2); the width of the vertex, 

 usually as compared with the basal segment of the antenna;, is also used, especially in specific determi- 

 nation. The facial fastigium, or fastigium of the front, is used in connection with the fastigium of the 

 vertex as a synoptic character, the feature usually considered being whether they touch or are distant 

 from each other, and if the}' do meet, whether the junction is in a transverse line (Plate, Fig- 3), or a 

 point (Plate, Fig. 4). The occiput, or top of the head, affords a character for the limitation of .some of 

 the subfamilies, the Bradyporinae and Saginae. In these groups the occiput is elevated considerably 

 above the fastigium of the vertex, while in most others it is but little elevated. In the groups where the 

 occiput is much elevated the antennae are inserted below the eyes, or between their lower borders, and 

 nearer the clypeal suture than to the top of the occiput (Plate, Fig. 2 I. The size and shape of the cms 

 and the structure of the mouth parts are also ot importance in classification. 



The thorax offers several taxonomic structures. The presence or absence of lateral carina and 

 transverse sulci on the pronotal disk, the development of the lateral lobes and the general shape ol the 

 pronotum, whether short and posteriorly obtuse (Plate, Fig. I 5 I, or long and posteriorly produced, or 

 acute (Plate, Fig. 16), are characters much used in classification, and the absence or presence of spines 

 on the prosternum is a point of much importance. The form of the meso- and metasternal lobes and of 

 the anterior border of the mesosternum are characters considerably used as are also those furnished by 

 the pits, or foveolae, of both the meso- and metasterni. 



The abdomen is not productive of many characters, with the exception of the genital organs. 

 Here, however, are otten found characters of great importance to the svstematist, the ovipositor 

 of the female and the cerci and the supraanal and subgenital plates of both sexes often proving 

 invaluable for generic and specific differentiation. 



The legs furnish the most used characters for the definition of groups. The shape of the tarsi, 

 whether depressed or compressed, and the presence or absence beneath of pads, or pul villi , are important 

 characters. The number of segments in the tarsi of the Locustida? is typically tour, but in one genus oi 

 Raphidophorinae the fore and hind tarsi are tetramerous, and in the aberrant subfamily Prophalango- 

 psinae all the tarsi are three-jointed. The first and second tarsal segments ate used in the definition oi 

 the subfamily Phaneropterinae, here being smooth laterally (Plate, Fig. 6), while in most groups 

 they are silicate laterally (Plate, Fig. 7). The form and armature of the tibia? and femora afford many 

 much used characters. The shape, whether rounded or sulcate on the various sides, and the presence or 

 absence of spines and spurs, especially the terminal ones of the posterior tibiae, are points of consider- 

 able taxonomic importance, as are also character of the anterior coxae, whether armed or not, and of 

 the geniculations oi the femora, whether rounded or developed into acute points or spines. The hearing 

 organs, or foramina, on the sides of the basal portion of the anterior tibiae, are of prime classi factory 

 importance. They are absent in the Gryllacrinae and some members of other groups, but, when present, 

 they occur in three forms which were defined and figured by Brunner von Wattenwyl i) over thirty years 

 ago. These organs are called tympani by some writers and foramina by others. Brunner called them 

 tympani, but I prefer foramina, as the singing areas of the tegmina of the male are usually called 

 tympani and to designate the auditory organs by the same name would be confusing. The three forms 



i) Verh. Zool.-bot. Ges. Wien, Vol. 24. p. 2S7 11874). 



