March, I9I2.] LeNG : ClCINDELID.^ IN EASTERN NORTH AMERICA. 7 



Manitoba and by Victor Shelford in Chicago. Showing first that 

 the imago does not wander far from the larval home, Criddle has 

 recorded patient investigations of the larvae, describing the burrows 

 they make in the soil, the nature and slope and moisture necessary for 

 each species observed and the length of time passed in the larval and 

 pupal stages. Shelford, repeating Griddle's observations, has studied 

 the species living on the shores of Lake Michigan where varied con- 

 ditions of slope, forest and moisture are found, and has determined 

 experimentally the insistence of each species upon its customary en- 

 vironment. A female Umbalis for instance, knowing that her larva 

 will require sloping soil of a certain degree of moisture, will not 

 oviposit in loose sand. A female 6-guttata will oviposit only in what 

 Shelford, following Cowles, calls climax forest, composed of beech, 

 oak and other deciduous trees. 



The bearing of th^se facts upon distribution is of great interest for 

 if the female flies only from one suitable habitat to another, and can- 

 not or will not fly to any great distance, it follows that any consider- 

 able interval of unsuitable soil will act as a barrier and retard the dis- 

 tribution of the species, even when suitable habitats exist beyond the 

 barrier. If the intervening unsuitable territory is sufficiently ex- 

 tended, it may even serve to isolate the favorable habitat as com- 

 pletely as if it were an island in the ocean. This I conceive is the 

 case in actual experience with riifiz'cnfris in the east plains of New 

 Jersey. There with the adjoining west plains, which I have not seen 

 but assume to be similar, is a peculiar piece of territory, in which 

 Mr. Davis and I found gravelly hills about lOO feet above sea level in 

 the midst of pine barrens. The very porous nature of the soil and 

 its slope conspire to produce so dry a condition that ancient oaks are 

 only i8 inches in height and the tallest pine tree we found was four 

 feet in height. In this situation lives a species, rnfivcntris, not found 

 elsewhere in New Jersey. Should the female wander from these hills 

 to oviposit, she could not find a similar locality in the entire state and 

 so year after year, century after century, rnfivcntris goes on inhabit- 

 ing this small piece of the earth apparently a prisoner forever. The 

 same appears to be the case with hcntaii confined to certain dry hills 

 in eastern Massachusetts and with some western species. 



Adaptability. — With every other factor equal there still remains 

 one that has evidently played an important part, /. c, the adaptability 



