220 



the change seems to be, as in the spectrum, from red to yellow, 

 then green, then blue, the intermediate steps between red and 

 green or red and blue being usually absent. 



Local Distribution of Species in the Sand Areas. The 



Insect Associations. 



A careful study of the life of a region soon enables one to 

 separate it into biological groups or associations, although in 

 the ultimate analysis nearly every species requires a shelf of 

 its own in the biological classification. It does not seem desir- 

 able in this connection to attempt more than a sketch of the 

 insect life of each of the various general types of environment 

 in the sand region. The observations here recorded are given 

 also in the annotated list which follows. 



One would not at first sight expect to see much life on the 

 areas of bare sand or with very scanty vegetation, (PL X., 

 XI1I.-XVI.,) but, in fact, all except the larger entirely barren 

 areas are busy scenes of insect activity, and there seems to be 

 no great change in relative numbers from year to year. The 

 exposed species of the blow-sand may receive attention first. 

 These are largely predaceous. Cicindela formosa generosa and 

 C. scutellaris lecontei are common everywhere (PI. XIV., Fig. 1; 

 XV., XVI.), and the light-colored and wary C. l&pida flits on 

 the bare sand in blowouts (PI. XIV., Fig. 1. 2). The vertical 

 burrows of their larvae may be seen opening here and there, 

 and the beetles themselves may be dug out of such burrows in 

 wet weather. Stachyocnemis apicalis likes to run over the sand 

 among thin vegetation (PI. XVI.), and is sometimes seen in ex- 

 cessive abundance. Returning to a locality where it had 

 been thus abundant the day before, rainy weather having set 

 in meanwhile, I could find only one or two anywhere in the 

 vicinity where they had just before been most numerous, and 

 these were hiding under dried horse-dung. Some were once 

 noted apparently feeding on a bit of fresh bird-dropping. Lep- 

 idoptera are not much in evidence here, except Eubaplie and 

 Crambus haytiellus, which are not infrequent. In the blowouts 

 (PL XIV.. Fig. 1) Mir robe mbex monodorda&vA Laphystia 6-fasciata 



