1967 ] 
Pinter — Widow Spiders 
291 
were preserved in a uniform manner. This was intended to reduce 
the problems resulting from ageing, e.g. differential fading and shrink- 
ing. Males were unavailable in sufficient numbers and were excluded 
from this study. 
I would like to point out that Gerschman de Pikelin and Schiapelli 
noted variations in the size and color of the successive egg sacs from 
a single female. After examining the same egg sacs, Levi (pers. 
comm.) attributed the color variation to an unequal accumulation 
of dust on each of the egg sacs. 
In a review of some North American Latrodectus , McCrone and 
Levi (1964) noted the distinct difference in the ventral abdominal 
patterns between L. mactans and L. variolus Walckenaer. This led 
me to study these familiar markings between the epigastric furrow 
and spinnerets. After examining several abdomens, I found that a 
few basic patterns were present on a majority of the specimens. 
These basic patterns and all variations of the basic patterns were 
sketched with the aid of a dissecting microscope equipped with an oc- 
ular grid. In this manner, the patterns from 266 specimens were 
compared. 
In alcohol the red and yellow-brown pigments fade or wash out 
and as a result all pattern colors appear yellow or reddish-yellow. But 
there was a distinct difference between the color of the preservative 
of population No. 2 and the preservative of the other populations. 
The solutions from the vials containing No. 2 were tinted a deep 
orange while the preservative from the vials containing Nos. 1, 3 and 
4 was usually colorless or rarely tinted with yellow. In order to 
obtain reproducible spectra from each of the species, Dr. Abalos sent 
additional specimens of Nos. 1, 2, and 3 which were preserved in 
alcohol. Additional specimens of No. 4 were unavailable. Upon 
receipt, each spider was washed in distilled water and 95% ethanol; 
the abdomen was divided along the mid-frontal plane; the internal 
organs and tissues of the ventral portion were excised ; the exoskeletons 
were weighed and placed in separate vials containing equivalent pro- 
portions (weight/volume) of 80% ethanol. The vials containing the 
samples and vials of normal solutions (80% ethanol to be used for 
calibration) were sealed with polyethylene caps and stored for 14 
months. This method was designed to provide uniform samples for 
analysis. With a Bausch & Lomb Spectronic 20 spectrophotometer 
measurements were made at 5 nm intervals between 380 and 650 nm. 
The solutions were used without purification or dilution, except 
where noted. Although the color of the solution was probably due 
