1967] 
McCrone — Latrodectus 
213 
O V M V M 
Figure 1. Vertical acrylamide gel electrophoretic patterns of the hemo- 
lymph proteins of female Latrodectus mactans (M) and L. var.olus (V). 
electrophoresis also gives excellent resolution but is less useful for 
taxonomic comparisons because it is difficult to run standard refer- 
ence proteins as controls in the same gels as the samples. In the case 
of Latrodectus hemolymph there is the additional advantage that the 
hemolymph from a single spider will form a distinct pattern in a 
single slot when the 8-slot slab is used. This allows a determination 
