86 E. A. OEITEEOD — ECOXOHIC EN'TOIIOLOGT. 



or thirty may be found in one turnip bulb, and smaller growths are 

 destroyed by the wireworm simply g-nawing through the root, and 

 then going on to a fresh plant.* From the larvae remaining in the 

 infested ground during the long period of feeding, all the successive 

 crops put in are subjected to their ravages, and (as the case may 

 be) successively injured or very possibly quite ruined. KoUarf 

 gives the larvae of Elater Imeatus as " laying waste entire fields ; " 

 and where wireworms are numerous and unattended to, the mischief 

 they cause only ceases with the destruction of everything in their 

 power. 



Amongst peas and beans, the pea- weevil clears off whole rows, 

 and is noted as first taking the peas, later in the year attacking the 

 beans, and then going on to the clover, and observations of the ex- 

 tensive and frequently-recurring ravages give it as "eating off the 

 early peas " — " committing dreadful ravages " — " peas, beans, and 

 other papilionaceous plants swarming with them," and so on, the 

 injuries in this case being the destruction of the leaves by the beetle. 

 The Bruchm granarius lays eggs in the foiTued peas sometimes to 

 the extent of every pea in the pod, and the black aphis attacks 

 the tops of the beans. The Silpha opaca, or mangel wurzel beetle, 

 brought under notice in England in 1844, destroyed the crops in 

 Ireland, and also in France, successive sowings being sometimes 

 swept off; X and, to take only a single instance more from the many 

 insects injurious to stored corn, the Calandra granarta, or granary 

 weevil, a small beetle which may literally be gathered up in hand- 

 fuls from beneath the com in neglected granaries, is calculated as 

 giving a produce of 6045 individuals from a single pair during the 

 warm part of the year between April and September, and as each 

 eg^ is deposited in a separate grain, the mischief is simply bound- 

 less. This affords one of the working examples of what may be 

 done by attention thoroughly directed to the subject. The yearly 

 loss to the great holders of grain would be something so serious if 

 the beetle were not kept under, that its habits have been studied 

 and the due remedy applied, whilst in small country holdings, 

 where it is considered quite beneath attention, it may be found 

 thriving, and I have seen half a wash-hand basinful of the beetles 

 swept up at once. 



Few who remember the thick clouds of Aphides which filled 

 the air for about thi'ee days a few years ago, will doubt their 

 immense power of increase given by Eeaumur,§ as 5,904,900,000 

 in five generations from one Aplm, the damage from them being so 

 great that in 1810 the pea-crop was injured throughout the country 

 to the extent of making it difficult to procure the requisite supplies 

 for the navy, and from the same cause it is stated that the difference 

 in the amount of the duty on hops is " often as much as £200,000 

 per annum, more or less, as the fly prevails or the contrary." || 



• ' Transactions of the Entomological Society,' vol. ii, p. 31. 



t ' Transactions of the Agricultural Society of Vienna,' vol. v, p. 105. 



\ ' Journal of the Eoyal Agricultural Society,' vol. viii, p. 405. 



\ ' Memoires pour servir a I'Histoire des Insectes,' vol. vi, p. 566. 



II Kirby and Spence, ' Introduction to Entomology,' 1867, p. 100. 



