DISTRIBUTE INSECT VARIETY. 311 



cuneiform tablets of an Assurbanipal and Nebuchadnezzar, and 

 how does this affect our handy calendars and storm-drums ? 

 There is one common defect observable in accounts given of locust 

 ravages, namely, an habitual disregard of the scientific name of the 

 noxious species observed. Thus, for instance, locusts reported to 

 have invaded Gibraltar and districts adjoining, on the 28th of 

 November, 1876, from specimens forwarded to the Entomological 

 Society turned out to be a Decticws [B. albifrons, Fab.) and not 

 locusts at all. 



The morass with reeds and water-lilies, where dragon-flies 

 of lineage old emerge from the amber wave, becomes the parade- 

 ground of migration, from whence species rise in clouds and 

 wing over the country to form new settlements. In Prussia the 

 villagers in Anhalt were alarmed one clear summer afternoon, 

 about 4 p.m., by a passing procession of the common flat-bodied 

 Llhuella dejoressa, that looked like locusts, and obscured the sun. 

 This well-watered district appears a rendezvous for these 

 rapacious insects, and in our fen districts the smaller vividly- 

 coloured species of Agrion have been similarly seen proceeding in- 

 land from the sea in numbers suflicient to cast a moving shadow 

 over the fields of Suffolk. At the end of June, 1867, the West of 

 Piedmont was invaded by a great number of Anax Mediterraneus , 

 De Selys, apparently brought by the wind from Africa. They 

 were noticed by Professor Craveri, at Bra, on the 1 8th of July, and 

 at Cuneo the 28th of the same month. On the 8th of August 

 they appeared at Turin and Venaria. Another flight of dragon- 

 flies arrived in the South of France in 1837, which, having 

 coupled, returned united to the sea. Many dragon-flies have 

 acquired a very wide distribution,"^ and these are " notorious wan- 

 derers.^' f Other migratory flocks of insects may be regarded as 

 due to an inordinate increase of their food, rather than to the 

 phenomena of love and rivalry. To this circumstance must be 

 attributed the autumnal showers of Lady-birds, Aphides, and 

 blight-devouring Hover-flies ; the destroyers and their prey so 

 frequently wind-driven from hop-fields and cultivated lands. An 



* Pantala Jlavescens, Fab., or Tholymls tillarga, Fab., for instance; or the 

 European Libellula quadrimaculata. 



t Kirby and Spence, Lettr. XVI.; M'Lachlan, Ent. 3Ioh. Mag., 1873, 

 p. 273. 



