1909.] . 209 



seem to be always more or less depressed, or at least flattened, alonf; 

 their occipital margins ; in some cases this depression is liardly 

 noticeable, in others it amounts to a definite and even sharp sulcat'on 

 (most conspicuous near the sides of the head), and in the latter case 

 the occipital margin sometimes, but not always, has quite the appear- 

 ance of a sharp carina. Every possible intermediate condition 

 between the mere " flattening " and the sharply margined " sulcus " 

 seems to occur in one species or another. But, unfortunately, it is 

 only in certain species that the presence or absence of a " sulcus " 

 appears to be a constant character ; and even in these it is probably 

 not absolutely to be trusted, though it is often useful to confirm or 

 throw doubt upon an identification otherwise arrived at. This char- 

 acter, also, is apt to display itself satisfactorily when, and only when, 

 the specimen is held in a particular position, and viewed in a particular 

 aspect. All which seems to point to the moral that there can be no 

 " royal road " to the determination of these insects, and that, however 

 carefully Tables may be constructed, they are certain sometimes to 

 mislead the students whom they are meant to help. 



I regret that though I have compressed these preliminary remarks 

 into the narrowest compass that I could manage, they still occupy so 

 much space that my actual " Tables of British Bolerus " will have to 

 wait for a further instalment of these papers. 



NOTES ON BRAC0NID2E, X.: 

 On the PACHYLOMMATINM, with DESCRIPTIONS OF NEW SPECIES. 



BY CLAUDE MOBLET, F.Z.S., F.E.S. 



In 1907 I examined a pair of Braconidce, which were quite un- 

 known to me and appeared to fall into none of the Divisions of that 

 Family set forth by Marshall (Bracon. d'Europ., i, 63). Upon closer 

 investigation T was struck by the similarity of certain features with 

 the aberrant *'Pachylomma hiiccata, Breb. ; and I have no doubt that 



* This genus has been thrice named : first, Fallen, in his "Specimen novam Hymenoptcra 

 disponendi methodum exliibens " (Lund, 1813), erected a genus Hybrizon, thus characterized— 

 "■ Antennis tenuis ; abdomine petiolato ; alarum areis costalibus aut tribus uut duabus ; areola in- 

 termedia areaque apeculari nullis" (Grav. Ichn. Burop., i, 61) ; and I am not persuaded that, with 

 the amplification given it by Nees von Esenbeck in 1834 (Hym. Ich. affin. Men., i, 27), it has not 

 as good a riglit to priority as many in general use to-da3', although it certainly is, in its original 

 form, utterly inadequate. Secondly, De Br(5bisson erected (Encycl. Metli., x, 23) his genus 

 Paxyi.omma in 1S25, which should fall, according to Verrall, through incorrect orthography ; for 

 which, cf. Westwood, Trans. Ent. Soc, iii, p. 278, et Mod. Class., ii, 136, fig. LCCIV. Lastly, it 

 was again brought forward by Curtis in his ' ' Characters of some undcscribed Genera and Species, 

 indicated in the Guide to an Arrangement of British Insects " (Ent. Mag., 1833, p. 188), under the 

 very appropriate name Planchus, by which it was for a yery long time known in Britain. 



