244 Benj. D. Walsh, on the Insects inhabiting the Gall* 



stiffly-gummed black buckram assumes a white streak in the place 

 where it has been frequently folded. For, 1st, although there is the 

 same kind of folds in the Ichneumonidous as in the Tenthredinidous 

 wing, yet there are never any complete bullar streaks in that family, 

 except the one passing through i^and G; 2nd, as Jurine has remark- 

 ed, there are very many Hymenoptera that have no bullae at all, to say 

 nothing of bullar streaks, though they have the same kind of folds to 

 their wings as Tenthredinidse ; 3rd, even in Tenthredinidse there are 

 certain folds in the wing which are not generally accompanied by a 

 bullar streak, even in those species which have the normal bullar 

 streaks fully developed ; e. g. a fold in the 1st discoidal cell, which 

 bears indeed a bullar streak in Dolcrus, but not in any other Tenthre- 

 diuous genus known to me, and the fold passing through the bulla M 

 which never bears any bullar streak in any genus known to me; ith, 

 in Eumi nidse and Vespidx, where the frout wing of each individual 

 living wasp is doubled up upon itself and undoubled perhaps a thou- 

 sand times a day, we generally find no bullar streak in the locus where 

 the doubling takes place ; and although this fold passes through the 

 bulla G, yet it passes through the vein on which F is placed, much 

 higher up than F, and without causing thei'e the least appearance of 

 any bulla, even in certain dark-winged Polistes (/meatus, Fabr. = 

 pallipes, St. Farg., annularis Linn., and rubiginosus St. Farg.,) which 

 possess a p 1 ale streak in the place where the folding takes place, and al- 

 so a regular system of bullae and bullar streaks. — Westwood. by the way, 

 has inadvertently asserted "that we look in vain throughout the whole 

 Order Hymenoptera, for any other iustance" of the wings being dou- 

 bled upon themselves, as they are well known to be in Diplopteryga. 

 (Introd. II, p. 238.) They are doubled upon themselves precisely in 

 the same manner in the Chalcidian genus Leucospis, and he had him- 

 self previously adverted to the fact. (Ibid. p. 164.) And in Leucospis 

 (ajfinis Say, 4 specimens,) we do meet with a pale streak, in the locus 

 where the folding takes place, though from the defective neuration of 

 the wing there is no visible bullar system. 



It does not follow, therefore, because the locus of the bulla? and of 

 the bullar streaks is in certain folds of the Tenthredinidous wing, that 

 consequently the folds cause the streaks and the bullae. Because in 

 the typical Tenthredinide there is a pale vitta, the locus of which is 

 immediately under the humeral suture, and because in the typical Ich- 

 ueumonide there is, in addition, another pale vitta, the locus of which 

 is immediately above the humeral suture, it by no means follows that 



