REVISION OF STREPSIPTERA — PIERCE. 



121 



7. Palpus arising from truncate tip of maxilla 8. 



Palpus arising some distance before tip of maxilla pecosensis. 



8. Subcosta and radius black, other veins brown; oedeagus at widest point 



abruptly rounded above wheeleri. 



All veins colored black; oedeagus at widest point rounded from rectangle. bowditchi. 



Key of females. 



A table based on the mandibles would be very hard to use, so the 

 following table, based on comparative measurements of the various 

 dimensions of the cephalothorax, is presented. The specimens 

 studied were mounted in balsam. 



The measurements are with a Zeiss stand, tube length 160, eye- 

 piece 2, objective A, with eyepiece micrometer (1 space = 0.0076 mm.). 

 As the comparative dimensions are the sought-for characters, other 

 microscopes will be just as available. The actual size of each 

 specimen may be found with its description. 



The following measurements were taken: (1) Length from base 

 of cephalothorax to apex; (2) length from line between apices of 

 spiracles to apex; (3) shortest distance between mandibles; (4) 

 breadth of head at base; (5) breadth of cephalothorax at spiracles; 

 (6) greatest breadth of cephalothorax. On account of the larger 

 size of these insects a lower power of microscope was used than in 

 Sty lops. 



Species. 



maximus. 

 pecosensis 



rubiginosi 



hubbardi. . 



texani 



pallidus . . 



bruesi 



hunteri . . . 

 wheeleri. . 

 nigrescens 

 bowditchi. 



Length. 



225 

 233 

 207 

 207 

 220 

 212 

 210 

 194 

 195 

 186 

 170 

 170 

 170 

 136 



2. 



3. 



Spiracle 



to 



apex. 



Breadth 

 between 



mandi- 

 bles. 



145 



43 



148 



47 



127 



38 



127 



44 



160 



40 



138 



31 



140 



36 



124 



31 



118 



43 



111 



37 



110 



29 



110 



35 



100 



38 



76 



38 



Breadth 



of 



head. 



195 

 180 

 178 

 180 

 155 

 145 

 140 

 124 

 170 

 148 

 127 

 137 

 128 

 148 



Breadth 



at 

 spiracles. 



Greatest 

 breadth. 



240 

 225 

 220 

 225 

 210 

 183 

 205 

 172 

 213 

 185 

 160 

 168 

 168 

 185 



200 

 230 

 220 

 225 

 222 

 189 

 205 

 178 

 216 

 187 

 164 

 174 

 172 

 189 



Following is a comparison of dimensions by ratio. The first col- 

 umn represents the ratio of the breadth of the cephalothorax between 

 the spiracles to the distance between the mandibles ; the second rep- 

 resents the ratio of the breadth of the head to the distance between 

 the mandibles ; the third the ratio of the breadth between the spira- 

 cles to the breadth of the head ; and the fourth the ratio of the breadth 



