FAM. MEMBRAClDiE 173 



Type atlas Goding. 



Goographical distribution ; The genus is known only from two Ameiican species both of which 

 aie very abundant in the western and southwestern part of the United States. 



1. atlas Goding, Ent. News III : iio (iSga). — Pl. 9, fig. 132. Utah, New Me.xico, Arizona, 



CaUfornia. 



2. soliis Goding, Can. Ent. XXXVII : 275 (i8g5). CaUfornia. 



154. GENUS TYLOCENTRUS VAN DUZEE 



Tylocentrus Van Duzee, Stud. N. A. Memb. 119 (1908). 



Characters : This is a genus which, while very distinct, is difficLdt to place in a synoptic key 

 because of the fact that the males are usually unarmed while the females generally show well developed 

 suprahumeral horns. As has been mentioned in the descriptions of certain of the preceding genera and 

 as will be seen in some of the following genera, the suprahumeral horns in the Membracida», while 

 among the most striking and quickly noted of all of the characters of the insects, are among tlie most 

 unreliable because of the variation within the species, as in the case of Tylocentrus, and because of the 

 gradation from one species and even from one genus to another as has been noted in Ceresa and 

 Stidocephala. 



The insects representing Tylocentrus are small in size and inegular in general facies. Head 

 subquadrangular, twice as bioadas high, roughly sculptured ; base sinuate and arcuate; eyes large and 

 ovate; ocelli prominent, equidistant from each other and from the eyes and situated a little below a 

 line drawn through centers of eyes; inferior margins of genae sinuate, horizontal, ilanged, edges turned 

 outward; clypeus veiy long, subquadrate, extending for four-fifths its length below inferior margins 

 of genae, tip blunt. Pronotum convex, highest above humeral angles. usually armed with suprahumeral 

 horns in the female, unarmed in the male, size, length and sharpness of the horns very variable; 

 metopidium sloping, broader than high ; median carina percurrent ; humeral angles heavy and blunt; 

 posterior process heavy, usualh' depressed at the base and strongly tectiform before apex which is 

 acute and extends a little beyond the internal angles of the tegmina; scutelhim weil exposed on each 

 side. Tegmina semi-opaque; base broadly coriaceous; venation very irregular and reticulate; tips 

 rounded ; apical limbus narrow. Legssimple; femora cylindrical, tibiae tiiquerate; hindtarsi longest. 



Type reticulatiis \'an Duzee. 



Geographical distribution : The two species represented in Tylocentrus seem to have a rather 

 limited distribution in southwestern United States and northern Mexico. 



1. quadricornis Funkhouser, Ent. News XXX : 8. 217 (1919). Arizona, Lower California, 



Mexico. 



2. rettculatus Wan Duzee, Stud. N. A. Memb. iig (1908). — Pl. 9, Texas. Arizona, Utah, Nevada. 



fig. 133. 



felinus Goding, Trans. Amer. Ent. Soc. LII : 889. io5 (1926). 



155. Genus LIRANIA STAL 



Lirania Stal, Rio Jan. Heni. II : 36 (1860). 



Characters ; This genus, which is known onl^- from the type species, is unknown to us and so 

 far as we know has never been recognized since its original description. It has been mentioned only 



