PRELIMINARY CATALOGUE 



OF THE 



ANISOPTERA 



IN THE VICINITY OF MANCHESTER, N. H. 



BY EDWARD J. BURNHAM. 



There is reason to believe that the Odonate type is slowly pass- 

 ing away. Representative of an ancient form of insect life, the 

 Dragon-flies find themselves lacking in adaptability to change of 

 environment. With many of our more recent forms change means 

 development ; with the Odonata change is extermination. Dory- 

 phora decemlineata, after feeding for centuries upon Solanum 

 rostratum in its home at the base of the Rocky Mountains, met 

 the outposts of civilization about the year 1859 and reached the 

 Atlantic coast in 1874, having in the brief space of fifteen years 

 spread over the intervening territory. Pieris rapse, introduced 

 from Europe, was first observed in Canada in i860; by 1886 it 

 had spread over a great part of the North American continent, 

 certainly southward to Florida and westward to Colorado. The 

 Odonata do not possess this power of adaptation to changed con- 

 ditions. A few species, notably Libellula quadrimaculata, have 

 been observed to migrate in large swarms ; but these migrations 

 were apparently undertaken in search of food rather than for the 

 purpose of oviposition. As a rule. Dragon-flies are non-migratory. 



Few groups of insect life so strikingly illustrate Darwin's obser- 

 vation that closely allied species cannot obtain in the same local- 

 ity, since of two species attempting to occupy the same situa- 

 tion and feeding upon similar food one must possess in some 

 respect a slight advantage, which will inevitably result in the ex- 

 termination of the weaker species. The extent to which this prin- 

 ciple has been carried among Dragon-flies constitutes one of the 

 most interesting features of a careful study of the Odonata in any 



