62 OBJECTIONS ANSWERED. 



some of them have even figured it ; and yet, strange to say, it was not 

 certainly known whether it was a flea (Pulex, L.), a louse (Pediculus, L.), 

 or a mite {Acarus, L.), till a competent naturalist undertook to investigate 

 its history, and in a short paper in the Swedish Transactions^ proved that 

 Linne was not mistaken in referring it to the former tribe, with which also 

 the more recent investigations of an eminent British Entomologist, I. O. 

 Westwood Esq., have shown that it must be arranged, though, from some 

 difference in its structure as well as habits, he has adopted the generic 

 name (slightly altered) proposed by the Rev. L. Guilding, and has called 

 it Sarcopsylla penetrans.^ 



The second instance of the insufficiency of popular description is even 

 more extraordinary. In 1788 an alarm was excited in this country by 

 the probability of importing, in cargoes of wheat from North America, 

 the insect known by the name of the Hessian fly, whose dreadful ravages 

 will be adverted to hereafter. However the insect tribes are in general 

 despised, they had on that occasion ample revenge. The privy council 

 sat day after day anxiously debating what measures should be adopted to 

 ward off the danger of a calamity more to be dreaded, as they well knew, 

 than the plague or pestilence. Expresses were sent off in all directions 

 to the officers of the customs at the different outports respecting the 

 examination of cargoes — despatches written to the ambassadors in France, 

 Austria, Prussia, and America, to gain that information of the want of 

 which they were now so sensible ; and so important was the business 

 deemed, that the minutes of council and the documents collected from all 

 quarters fill upwards of two hundred octavo pages.^ Fortunately England 

 contained one illustrious naturalist, the most authentic source of informa- 

 tion on all subjects which connect Natural History with Agriculture and 

 the Arts, to whom the privy council had the wisdom to apply ; and it was 

 by Sir Joseph Bank's entomological knowledge, and through his sugges- 

 tions, that they were at length enabled to form some kind of judgment on 

 the subject. This judgment was, after all, however, very imperfect. As 

 Sir Joseph Banks had never seen the Hessian fly, nor was it described in 

 any entomological system, he called for facts respecting its nature, propa- 

 gation, and economy, which could be had only from America. These 

 were obtained as speedily as possible, and consist of numerous letters from 

 individuals, essays from magazines, the reports of the British minister 

 there, &,c. &c. One would have supposed that from these statements, 

 many of them drawn up by farmers who had lost entire crops by the insect, 

 which they profess to have examined in every stage, the requisite informa- 

 tion might have been acquired. So far, however, was this from being the 

 case, that many of the writers seemed ignorant whether the insect be a 

 moth, a fly, or what they term a bug. And though from the concurrent 

 testimony of several, its being a two-winged fly seemed pretty accurately 

 ascertained, no intelligible description was given from which any naturalist 

 could infer to what genus it belonged, or whether it was a known species. 

 With regard to the history of its propagation and economy the statements 

 were so various and contradictory, that though he had such a mass of 



* Swariz in Kongl. Vet. Ac. Nya. band. ix. 40. 



2 Trans. Enl. Soc. Lond. ii. 199 — 203. ^ Young's Annals of Agriculture, xi. 406. 



