224 NORTH AMERICAN EUMASTACINAE (oRTHOPTERA) 



(vicinity of Prescott). In much of this area it is not present, 

 requiring favorable zonal conditions for its occurrence. Both 

 of our genera are almost entirely limited to the Upper Sonoran 

 Life Zone in their distribution. Nothing whatever is known of 

 the distribution of the two North American genera south of the 

 Mexican line. 



Both of the genera found in the United States belong to the 

 section Eumastaces, or restricted subfamily Eumastacinae if the 

 group is called a family (Eumastacidae), as done by Burr. Their 

 relationship is clearly with Masyntes Karsch, as indicated by 

 Scudder and Burr in the case of Morsea, no close affinity existing 

 with Eumastax, Paramastax and Scirtomastax, the other genera 

 of the section. Our two genera are, however, much more nearly 

 related to one another than either one is to the West Indian and 

 South American Masyntes. Both genera are completely apterous, 

 without continuous or definite lateral carinae on the pronotum, 

 the caudal margin of the disk of which is appreciably emarginate 

 mesad, the fastigium is produced and entire, with the dorsal 

 section of the frontal costa broadened. From Masyntes, Morsea 

 and the new Psychomastax can be readily differentiated by having 

 the spines of the internal margin of the caudal tibiae uniform in 

 length, bj^ their apterous condition and entire and produced 

 fastigium.2 



In habits all the forms found within the territory considered 

 are thamnophilous, being particularly fond of perching on the 

 tops of various species of bushes, spiny or otherwise, which make 

 up the chaparral of the western or coastal slopes of the southern 

 Calif ornian and Coast Range Mountains. In such situations you 

 will, by careful scrutiny, find them with short antennae erect and 

 parallel, caudal limbs akimbo, the whole insect picturing alertness 

 and vigor. Their ability to jump is developed in full proportion 



2 A feature of interest in both of the genera here studied is the presence on the 

 ventral surface of the ninth to tenth antenna! joint of a distinct, though 

 minute, spiniform tooth, in both sexes. In examining representatives of seven 

 other genera of Eumastacinae we find a similar development indicated as 

 follows : 



Present on the eleventh segment in Erianthus malcolmi, cf ; Erucius vitreus, 

 cf and 9 ; Eriicius dimidiatipes, c? ,' Masyntes gundlachi, 9 . 



Present on the twelfth segment in JJruci^is magnificus, cf . 



Present on the ninth segment in Thericles gnu and quagga, 9 . 



Not indicated in Brachytypus burri, Episactus hrunneri and Masyntes iigris. 



