1915.] NATURAL SCIENCES OF PHILADELPHIA. 301 



degrees the cephalic color pattern found in the species. Other 

 names: cubensis, aztecus, galapageius, harretti. 



D, suffused Z, (normally d to f, v) 3 (often weakly 0). mexicanus 

 Saussure.^^ 



This variant is widely distributed over Mexico and Lower Cali- 

 fornia, it is the development toward an arid adaptation of the assimilis 

 type and shows great variability. In the United States occasional 

 individuals show a tendency toward, and a few specimens are typical 

 of, this condition in our series taken along the Mexican border of Texas. 

 In this variant the pronotum has the dorsum frequently' narrowly 

 bordered laterad by pale yellowish. Other name: chichimecus. 



EZ, (normally d to g, u), 2 (often weakly 0). personatus Uhler.^- 



This variant, a desert adaptation, in which the extreme of recessive 

 coloration and most strongly defined color pattern is reached, is 

 known only from the United States from Kansas, Colorado and 

 central Texas westward. Of all the variants of the species this one 

 shows the most decided indications of a geographic race in process of 

 evolution. It is interesting to note that this variant averages decid- 

 edly heavier than the other desert adaptations of the species found 

 in the southwestern United States. Other name : Stal's much older 

 name, lineaticeps, appears to represent a transition between this and 

 the mexicanus variant. 



A, suffused Z, (normally d to g, u), 3. armatus Scudder. 



In the same regions of the southwestern United States in which the 

 personatus variant is found, the present variant also occurs, often very 

 conspicuous on account of its dark head and pronotum which contrast 

 strongly with the much paler remaining portions of the insect. 

 Great variability is shown in the series before us, many differences 

 being found in individuals of every large series, but none showing any 

 approach to the personatus variant. Immature individuals of this 

 variant might be mistaken for those of Miogryllus Uneatus; they have, 

 however, the abdomen broadly infuscated, giving them a barred 

 appearance, while the spines of the dorsal margins of the caudal 

 femora are rarely less than 6 in number, in M. Uneatus normally 5, 

 and the young of the same are more uniformly yellowish. Other 

 name: alogus. 



B, suffused Z, (normally d or e, w) 2 (usually weakly indicated 0). 

 scudderianus Saussure. 



This variant occurs in sandy areas in the eastern United States, 



11 See Plate IV, Fig. 4. 



12 See Plate IV, Figs. 2, .5, 6, 7. 



