402 



colour, and thus directly aid in producing the endless variety of 

 nature." 



" Local forms " are perhaps what are most likely to come under 

 the notice of the local entomologist, or what at least he should look 

 for, reference being had to the physical and geological features of 

 particular situations. Sand-hills and sand-plains, chalkpits, marshy 

 spots, the undrained residuum of extensive fens that existed 

 formerly, but which have long since disappeared, mountainous 

 ravines and glens, or hills composed of the older rocks thrown up 

 amid the newer; all these places not only have their peculiar 

 species, but are likely to impart apeculiar character to other species 

 also found in them, though at the same time free rangers over the 

 country around.* It needs, of course, much inquiry and com- 

 parison to ascertain the fact of such peculiarities, for which it is 

 necessary to examine other local collections ; and any similar con- 

 ditions of soil, &c., occurring in two different localities in which the 

 same form prevails should be carefully noted. 



Cases of " dimorphism" and " polymorphism," which have only 

 of late years attracted the attention of naturalists, and which are 

 now found to be so frequent both in the animal and vegetable 

 kingdoms, should be equally sought for, and wherever suspected to 

 exist, the economy and habits of the species in question must be 

 closely looked into, which will often throw light on the phenomenon. 



We are all familiar with the phenomenon itself as exemplified 

 in some of the social Hymenoptera ; the hive-bee, for instance, in 

 which there is a second imperfect form of the female, the neuter or 

 worker bee ; and the different species of ants, in which we find three 

 or more- distinct forms associated together in the same nest, each 

 form being " specialised to a distinct function in the economy of 

 the species." British coleopterists in this country have also long 



* Thus Elaphrus riparius in sandy districts is said to be " of a clear brown 

 colour, in meadow lands green." — Ent. Trans., 3rd Ser., vol. v., Proceed., p. 

 cxxiv. Gnophos pvllata is said to be " found nearly white on the chalk downs, 

 and to vary from nearly white to sooty black according to the geological for- 

 mation of the locality where it occurs." Again, Apion germari, when found 

 on Mercurialis perennis to be constantly of one form, and when found on 

 Mereurialis totnentosa constantly of another form." — Ent. Trans., 1870, 

 Proceed., p. xiv. 



