GENUS DERMACENTOR KOCH. 43 



3. Stigmal plate about as broad as long, with short and broad dorsal pro- 



longation, and covered with many very minute granules, scarcely visi- 

 ble as such; shield plainly longer than broad, and much streaked with 



white variaMlis, 



Stigmal plate with much larger granules, at least near the peritreme — 4 



4. Stigmal plate without distinct dorsal prolongation ; shield plainly 



longer than broad 5 



Stigmal plate with a more or less distinct dorsal prolongation 6 



5. Shield mostly white, with brown streaks and spots ; porose areas close 



together albipictus. 



Shield dark red-brown, with very little white; porose areas rather 

 widely separate nigrolineatus. 



6. Shield mostly white, about as broad as long 7 



Shield without white, or but little, plainly a little longer than broad ; 



porose areas but little longer than broad, and well separated. 



parmnapcrtus. 



7. Porose areas very small; stigmal plate with rather wide dorsal prolon- 



gation occidentalis. 



Porose areas larger; stigmal plate with a more narrow dorsal prolon- 

 gation veniistus. 



8. Stigmal plate with from four to ten very large isolated granules; 



dorsum without white marks; only eight impressed lines behind — nitens. 

 Stigmal i)late with many smaller, more crowded granules ; twelve im- 

 pressed lines behind 9 



9. Stigmal plate about as broad behind as long, with dorsal prolongation, 



the granulations extremely minute; dorsum marked with white 



streaks and spots variaMlis. 



Stigmal plate usually plainly longer than broad ; the granulations 

 much larger 10 



10. Stigmal plate without distinct apical prolongation ; the sides of body 



more nearly parallel 11 



Stigmal plate with distinct apical prolongation; sides of body more 

 divergent 12 



11. Dorsum mostly white, with brown streaks and spots in a pattern ; hind 



angles of the capitulum but little produced; coxa IV about one-half 



as long as broad on base; large species albipictus. 



Dorsum red-brown, with black lines, no white; hind angles of capitulum 

 much prolonged ; coxa IV not twice as broad on base as long ; species 

 of moderate size nigrolineatus. 



12. Dorsum with few, if any, white spots; coxa IV about as long as broad 



at base: hind angles of capitulum moderately i)roduced parumapertus. 



Dorsum largely white, or much spotted with white 13 



13. Stigmal plate more attenuate behind ; coxa IV about one-half as long 



as broad at base; hind angles of capitulum moderately produced- vcnustus. 

 Stigmal plate less attenuate behind ; coxa IV not twice as broad on base 

 as long; hind angles of capitulum much produced occidentalis. 



Dermacentor bifurcatus Neumann. 



This species was described as an Ixodes, and based on a young 

 female from a wild cat, from Texas. Later Neumann placed it as 

 a synonym of Ixodes hrvnneus Koch, then still later stated that it 

 was a Dermacento7\ It is, therefore, evidently a nymph of some 



