466 
Psyche 
[September-December 
Thoracic groove form is correlated with pars cephalica shape. Those 
specimens (Sierra Madre and Henninger Flats) with an exception- 
ally elongate pars cephalica lack any vestige of a thoracic groove 
(Fig. 51). Specimens with a more normal pars cephalica possess at 
least a vestigial thoracic groove in the form of a shallow depression 
(Fig. 50). Tehachapi Mountain specimens have slightly to markedly 
deeper thoracic grooves than other specimens. 
Tehachapi Mountain males have two or three trichobothria dor- 
sally near the distal end of metatarsus IV. All other A. thompsoni 
males as well as all other Aliatypus males have only one tricho- 
bothrium in that position. Variation in palpus conductor tip form 
is illustrated by Figures 111 to 113. The Tehachapi Mountain con- 
ductor tips (Fig. hi) are slightly but consistently different from 
those in all other samples. Tehachapi Mountain males tend to have 
a darker pars cephalica and chelicerae, and redder pedipalps than do 
other specimens. The Las Barras Canyon specimens have noticeably 
more elongate legs (Fig. 29) than most others. 
Fe?nales: A few female characters exhibit strong geographic vari- 
ation. These are characters which also vary strongly in the male 
sample, and the geographic patterns of these variations are like those 
in the male sample. 
The pars cephalica is markedly more elongate in the Sierra Madre, 
Eaton Canyon, and Henninger Flats samples than in all other sam- 
ples (Figs. 31, 52-53). These same three southeastern samples have 
on the average a considerably broader sternum than most other sam- 
ples (Figs. 32, 71-73). The thoracic groove is completely absent in 
these three samples with an elongate pars cephalica (Fig. 53), and is 
only a faint depression (slightly more heavily sclerotized than its 
immediate surroundings) (Fig. 52) in all other samples except the 
Tehachapi Mountain and Kernville samples. These latter specimens 
have a slightly deeper depression or a shallow pit. 
The Tehachapi Mountain and Kernville specimens have two to 
four trichobothria dorsally near the distal end of metatarsus IV. All 
other females of A. tko?npsoni and all other Aliatypus species have 
only one such trichobothrium. Variation in seminal receptacle form 
is illustrated by Figures 155 to 171. The Tehachapi Mountain and 
Kernville specimens have shorter receptacle stalks and fewer loops 
per stalk than other specimens elsewhere. The centrally located popu- 
lations (Baldwin Hills, Pacific Palisades, Las Barras Canyon, Lime- 
kiln Canyon, Chatsworth, and Placerita) all have a dense cluster of 
short stout setae at the anterior median edge of the carapace, while 
