518 DESCRIPTION OF SOME 



occurs that a writer distinguishes one species from another, in 

 his specific character, by terms of comparison, as " larger or 

 less," " broader or narrower," " smoother or more punctured," 

 &c. &c. " than the preceding," or than some other ; a mode of 

 description vague and unsatisfactory, and obviously useless in 

 all cases where the investigator does not possess " the pre- 

 ceding " or the standard of comparison, a case of constant 

 occurrence. Such a mode of description ought to be avoided. 

 It is no doubt true that perfectly distinct species are so closely 

 allied, that the line of separation is but slender ; still, slender 

 as it may be, it must be such as is capable of being expressed 

 in words, and it is the more necessary to use great care in 

 giving prominence to the definition of this slight character. 

 I am well aware how trite these observations are, and how 

 forcibly they have been expressed in your first volume ; but so 

 long as we find they are neglected by writers, it cannot be 

 unnecessary to call their attention to them. A hint may be of 

 value, — it may induce future describers to look carefully to the 

 execution of the task they undertake, so that their labours may 

 be as useful and as highly esteemed as their intentions are 

 laudable. I would entreat them to weigh well the admirable 

 observation — " Character non est ut genus fiat, sed ut genus 

 dignoscatur." If they desire a model, let them imitate the 

 unequalled Monog. Apum Angliae of the venerable, the be- 

 loved Kirby; or the justly popular work of the distinguished 

 Gyllenhal. 



Art. L. — Descriptions of some British Species of Anacharis. 

 By Francis Walker. 



An acharis, 3 Dalman. — ( Hymenoptera Cynipites.) 



Corpus angustum, convexum, atrum, nitens, Iseve, compactum, parce 

 et breviter hirtum : caput mediocre, transversum, subquadratum, 

 thorace paullo latius, sulculispostice trans versis ; vertex inter ocellos 

 elevatus : oculi mediocres, laterales, globosi, obscure rufi: ocelli in 

 triangulo supra verticem positi ; medius paullulum ante laterales 

 prostans : mandibulae mediocres, arcuatae, dentibus magnis acutis 

 3 armatae : maxillae longse, graciles, subarcuatse ; lacinise acumi- 



J 'Ava, retr6 ; Kiipco, abscindo. 



